Major update of my article on digital darkroom lighting

Discussion in 'Digital Darkroom' started by frans_waterlander, Jun 10, 2013.

  1. I've updated my article on digital darkroom lighting. You can find it here:
    http://solux.net/ies_files/Digital%20Darkroom%20Lighting%202013.pdf
    The major points/updates are:
    - monitor gamma has nothing to do with the non-linearity of human vision
    - new list of sRGB and Adobe RGB monitors with IPS panels
    - why 6500K is so prevalent
    - why prints often come out too dark
    - working in total darkness is a surefire way to develop bad habits and get bad results
    I have no ties to SoLux other than liking their products.
     
  2. Your list of available IPS monitors I found helpful and reassuring and pretty much what I've found so far on my own after my Dell 2209WA developed distracting non-uniformity artifacts just a year after its 3 year warrantee expired.
    One thing I can't seem to get a thorough answer online even from Dr. Soneira of DisplayMate.com is how to detect whether some of these newer (and cheaper) sRGB gamut LED backlit displays have 8 bit or 6 bit +A-FRC panels. From what's been mentioned over at tftcentral some of the Asus and Dells you've listed come with 6 bit panels.
    Got tired of buying displays online hoping I'ld get one that came with a decent IPS panel and decided to try out the LG 27ea63v-p from my local Best Buy ($330). I did the typical gradient tests and can't see any dithering or severe banding. I also developed a lowered saturation complementary color purity gradient test on 3 layers inverting and changing blend modes to try to see any signs of the LG being a 6 bit and couldn't.
    It's gamut after profiling with the Colormunki Display is a bit less than sRGB in blues, cyan and red but juts out beyond in greens and yellows. All my images look the same as on the Dell so I guess I got me a good enough monitor for photo editing.
    00bjHG-540722684.jpg
     
  3. Speaking of sRGB and Adobe RGB coverage, you can get the wider gamut coverage in your phone if you want:
    http://www.phonearena.com/news/UL-certifies-the-4.99-FHD-display-on-the-Samsung-Galaxy-S4_id43874
    Doug
     
  4. From Doug's link...
    According to UL, the screen on the Samsung Galaxy S4 offers one of the best color reproductions in the mobile industry with the broadest color gamut of up to 97% for the Adobe RGB color space.​
    If they don't implement color management technology their version of "best color reproduction" will look like a circus side show. I'm so glad I don't own a mobile phone.
     
  5. It's not like Samsung doesn't know about this issue with wide gamut color devices if they can include it somewhat in their sRGB HDtv's like their UN32EH4003 I got at Walmart. They call it "Wide Color Enhancer". What wide color are they enhancing for on an sRGB tv? Is HD content in a wide color space? Not from what I'm seeing. Or is this specific to BluRay content?
    00bjNj-540732084.jpg
     
  6. Tim wrote: "From what's been mentioned over at tftcentral some of the Asus and Dells you've listed come with 6 bit panels."
    Absolutely not! All the monitors on my list are 8 bit or higher.
     
  7. Can you prove it, Frans? Really! I mean it! I don't have a slew of panels to compare against. That's why I resorted to buying local so I can take it back without the shipping hassles and waste of time. Do you have a test for determining bit depth on these monitors? I'ld really like to try it out.
    I can't find anyone online to prove whether those displays come with an 8 or 6 bit panel. The manufacturers aren't talking and in fact according to the REALLY long discussions at AVSforums they're now deliberately concealing the manufacturing codes that indicate each particular model's panel technology.
     
  8. This cnet review of the Dell U2410 doesn't suggest it's not an 8 bit panel but the descriptions of the visual anomalies indicates the reviewer must have gotten a bad "not so perfect" build version of this model in the review posted below...
    Static dithering in the shadows?! Pinkish hue in whites?!...​
    Huh?! I don't even get that on my $300 Dell and current LG 27"!
    http://reviews.cnet.com/lcd-monitors/dell-ultrasharp-u2410/4505-3174_7-33772972.html
    I wish congress would do something about forcing these display manufacturers to be truthful and forthright about the most important component they're including in these displays...THE FREAKIN' PANEL TYPE AND BIT DEPTH! HOW HARD CAN THAT BE?!
     
  9. Look it up in product reviews, manufacturers' specifications and websites like prad.de/en and tftcentral.co.uk.
     
  10. Frans, I believe I already indicated I did that. Yes, their specs say they're 8 bit panels for the copies they reviewed. That's not what I was talking about which I thought I made clear with the Dell U2410 cnet review.
    Over at AVSforums they're calling it the "Panel Lottery" issue when purchasers who are not established online reviewers get their copy of the same model only to find the panels have been swapped for either better grade (like the IPS panel that came with my Samsung HDtv) or less desirable MVA and even TN panels.
    http://www.avsforum.com/t/1406151/the-official-2012-samsung-eh4000-eh5000-eh5300-owners-thread/1440#post_23412205
     
  11. Okay, I took your advice and recalibrated my monitors to 5000K. This is gonna take some getting used to; we'll see how it works out...
     
  12. I couldn't take it. I've already backed off to 5800K.
     
  13. Tim,
    Do you have any more specific references to this so-called lower-bit-depth-panel-swapping than a 49 page thread? In the past Dell was notorious for swapping TN and IPS panels in "their" monitors, but that is as far as I can tell way, way back in the past. It would be nice to back up your claim about the Dell and, I believe the ASUS monitors, with more than hearsay.
     
  14. Mark,
    You make my point exactly about people developing bad habits. 5000K is way more in line with the real world than anything higher than that. Did you compare your 5000K screen image with a printed version? How did that compare?
     
  15. I didn't get as far as printing anything; in the past I've felt I had a reasonable match at 6500K. Just couldn't take how muddy everything looked. I'll let myself adjust to 5800K for a week or so, then maybe I'll try 5000K again, along with some print testing. I've never felt that the lighting in my work environment really matches the (highly variable, not controlled by me) lighting where my prints are hung anyway...
     
  16. Mark,
    The mismatch I'm talking about doesn't apply between the computer screen where you do your image editing and a viewing environment outside of your digital darkroom. It's the mismatch between your screen and the print when viewed in your digital darkroom lighting.
     
  17. I was persuaded by the argument that the lighting where my prints are hung (again, not under my control) is typically going to be considerably warmer than 6500K.
     
  18. digitaldog

    digitaldog Andrew Rodney

    The CCT K value you calibrate to is all over the map. For one, you can calibrate with instrument A, software package A and get one result, use the same instrument and package B and get another result. There are a number of reasons for this.
    Next, the only value that makes any sense is the one that produces a color appearance that matches whatever you want to match (usually a print). As a print is illuminated by something, that plays a huge role so the value you enter into the software is going to vary. Next, the type of illuminate used in the panel will play a big role too. I just read a fascinating article by Abhijit Sarkar's recent submission to CIE regarding his work on Standard Observer. I don't think it's out for public consumption yet but in the piece, there's mention of an experiment where users were asked to match via a display using differing back light an image they are viewing in a booth. Two displays were both calibrated using the same product to 5200K. Both displays had quite different SPDs as one used CCFL, the other LED and the spectrum of the two are vastly different. They saw colors on one display being much warmer than the other, the results of the differences of the match they made was between 3 and 13dE (76), the average for all users was a dE of 8! Mostly in the aStar. All viewers were checked for color blindness and scored high in the FM100 hue test.
    Anyone that tells you to calibrate to this CCT or that cd/m2 without having the print viewing conditions in mind, and based on this piece, the type of display technology isn't providing much useful in the advise. The numbers DO NOT MATTER unless you've got a group of really high end reference display systems in a collaborate group and everyone is expected to see the same results. And this doesn’t mean the numbers everyone agrees on is correct, but at least consistent.
     
  19. Andrew,
    My article makes very clear that the color match I'm discussing is the one between the image on the screen and the print of the same image viewed in the digital darkroom lighting. I also emphasize that the brightness of the screen and print need to be matches as well, and I describe how to check for those matches. I also advise to use 5000K for the monitor with gamma 2.2 (very important as well to compensate for the distortion caused by gamma encoding) and the use of SoLux 5000K bulbs.
    Your comments, while I know that they are not ment to be intepreted as such, can easily be interpreted by the reader as "anything goes", something that is absolutely not the case.
    The numbers matter a lot when you want the image on the screen to closely match your print, so there is a strong correlation between the two; without such correlation it becomes difficult to do any meaningful editing. The print provides feedback and if there is no good match, that feedback becomes meaningless at best and misleading at worst.
    I personally don't put much value on any study that uses fluorescent or LED lighting because of the horrendous peaks in their power spectrum.
     
  20. digitaldog

    digitaldog Andrew Rodney

    My article makes very clear that the color match I'm discussing is the one between the image on the screen and the print of the same image viewed in the digital darkroom lighting.​
    Every lighting condition, even the intensity of the same illuminant and every backlight will affect what is possibility an effect upon viewer metamerism and again, the software and instrument you use has to be identical to the reader if you (and they) expect the same results.
    I also advise to use 5000K for the monitor with gamma 2.2​
    Again, 5000K is a range of colors and pretty meaningless based upon the context of what I wrote! And TRC gamma is meaningless in ICC aware app's. Further, there are advantage to some display systems using a native gamma setting IF the software supports it.
    Bottom line is advising people to use fixed settings without them using absolutely identical components (display with defined backlight, instrument+software, viewing conditions) does far more harm than good. YMMV! So will theirs.
    Your comments, while I know that they are not ment to be intepreted as such, can easily be interpreted by the reader as "anything goes", something that is absolutely not the case.​
    Actually that's spot on unless we are discussing identical hardware and software. Further, ignoring viewer metamerism, even each individual's perception of color isn't a good idea. This is exactly why the piece I referenced exists! It points out the folly of trying to suggest simplistic settings and advise without specific hardware, software and viewing conditions is a waste of everyone's time.
     
  21. digitaldog

    digitaldog Andrew Rodney

    I've never felt that the lighting in my work environment really matches the (highly variable, not controlled by me) lighting where my prints are hung anyway...​
    This begs the question, if the print isn't anywhere near the display, how would you know there's a match between the two?
     
  22. Andrew,
    Instead of critisizing what I wrote as meaningless and harping on what all could go wrong, maybe you should follow my advice and see for yourself how a 5000K monitor compares to the print viewed with SoLux 5000K lighting after the brightnesses of the monitor and lighting have been matched as described in my article. I'd be very interested to hear how that works out for you.
     
  23. digitaldog

    digitaldog Andrew Rodney

    Instead of critisizing what I wrote as meaningless and harping on what all could go wrong, maybe you should follow my advice and see for yourself how a 5000K monitor compares to the print viewed with SoLux 5000K lighting after the brightnesses of the monitor and lighting have been matched as described in my article. I'd be very interested to hear how that works out for you.​
    I never said your piece was meaningless, it has some very good points. Next, I do have Solux viewing conditions and no, 5000K doesn't work on this end with an NEC SpectraView II anywhere as well as the settings I had to find by trial and error to produce a visual match. Next, if you read what I wrote, you'll see we are in agreement in a number of areas including how differing SPD's of both print viewing and display backlight can affect this match. You also may wish to consider the piece I referred to and the results whereby depending on the SPD, a dE difference of as high as 13 was seen on two differing display technologies. That's due to viewer metamerism failure. Based on both our understanding of just how the backlight of a display can alter the results, how can you say that everyone should calibrate to 5000K? Are you certain that every instrument used to calibrate a display, mated with all the various software products that have a setting for 5000K produce identical results? You certainly understand that 5000K is correlated, the only way to really get a display to produce that would be to heat it until it was a pool of molten plastic. That the blackbody is a theoretical object and that yes, your mileage will vary, a lot and that simply expecting everyone to set 5000K and get a match is impossible. IF that were not the case, why is it that higher end systems like Eizo and NEC provide such precise control over differing white point settings? CCT Kelvin values in one value increments, the ability to enter chromaticity values, even the ability to measure with an instrument the viewing conditions? Why not have a single setting in such software products: 5000K? Because that one size fits all WP doesn't work for everyone, not even close.

    The answer is clear. 5000K is a range of colors, doesn't ensure any kind of match to anything and varies by instrument and software package. You ask: "anything goes", something that is absolutely not the case. When in fact, that is the case. The correct numbers, which vary are the ones that produce a match for you (or anyone else).
    Do you have a Spectrophotometer that can read the Solux bulbs? I assume you do since you show SPD's in your article. What's the Spectrophotometer say the CCT value is of the Solux bulbs? 5000K on the money?
     
  24. Andrew,
    What do you mean by "SoLux viewing conditions"? Do you use the SoLux "5000K" bulbs? Do you have any other lighting in your digital darkroom? Is there no outside light getting in? Do you have a neutral "color" scheme in your digital darkroom? Does the brightness of the monitor match that of your prints? And what are the settings that you use with your SoLux lighting?

    I don't have a spectrophotometer; the SPD curve is straight from the SoLux website, with permission. The datasheet on the SoLux website states the CCT for the "5000K" bulbs as 4901K at 12 Volt and the CRI as 98. And yes, when I calibrate my monitor I select 4900K and a gamma of 2.2.
     
  25. digitaldog

    digitaldog Andrew Rodney

    Do you use the SoLux "5000K" bulbs?​
    No I don't use them nor recommend them! Do I own and have I tested them? Yes. I have probably every Solux product you can buy and some you can't. You'll find my name on their web site (http://solux.net/cgi-bin/tlistore/infopages/color-proofing.html). I've written about them for nearly a decade: In my book (2005), including how to build a print viewing system with them. I've written about them in print (http://www.ppmag.com/reviews/200604_rodneycm.pdf) and in presentations (Epson Print Academy). I tested their PAR's before release and was asked by Solux to write a letter on their behalf about my needs as a industry expert for such bulbs to petition congress to allow them to continue to make and sell them!
    The only reason Solux introduced more recently a bulb labelled 5000K is to make people like yourself happy with a number! It is the same bulb as their 4700K with an increase in voltage which shortens the life and cost you more to buy. This is why I do not recommend them but I understand how buyers would strongly wish to have a bulb with such a value, especially after reading articles like yours. There is no need for this bulb and in fact, depending on the proofing work you are doing, you're better off with the CCT 4100K blub! When I was teaching for Art Wolfe in his studio/gallery/class, we did testing with both 4100K and 4700K and the former was far better for viewing prints and proofing. The 4700K's are too cool appearing for many. For my needs, I use Solux CCT4700K (and a GTI Fluorescent booth).

    There are Fluorescent bulbs ranging from $1 to far more that have 5000K on them. Do you believe they are identical and produce 5000K? But enough questions here, I answered yours about my use of Solux products, how about you answer the questions I posed to you above.
    I don't have a spectrophotometer; the SPD curve is straight from the SoLux website, with permission.​
    I do have a Spectrophotometer and the plots you see in the article were measured by me. You're not equipped to evaluate color temp if you don't have such an instrument, sorry. As for my studio/lab, I have a very well designed color reference environment. I've setup multi-thousand dollar systems for clients who's viewing and proofing needs require precision to a level of less than 1dE!
    Sorry you're put off by peer review. Maybe you would consider sending the PDF to say Chris Murphy or Phil Brandfield at Solux. But the bottom line is, suggesting a fixed value to set for display calibration without taking a number of important factors into consideration does more harm than good. Those factors have been presented to you more than once, I would ask you look them over and reply. Or ignore them, doesn't matter to me, might to anyone reading your updated piece.
     
  26. Two displays were both calibrated using the same product to 5200K. Both displays had quite different SPDs as one used CCFL, the other LED and the spectrum of the two are vastly different. They saw colors on one display being much warmer than the other, the results of the differences of the match they made was between 3 and 13dE (76), the average for all users was a dE of 8!​
    I think you're on to something there about the different backlight spectra. This LG 27" though slightly smaller than sRGB still exhibits an overall lack of saturation and richness viewing sRGB content.
    I emphasis overall because, if I look directly and focus on each individual graphic element (i.e Colorsync Logo with the Spinning Wheel colors) or photo, color managed or not, whose content has been written to the sRGB space, they match what I see on my Dell 2209WA whose gamut is slightly larger than sRGB and has a CCFL backlight.
    Step back and look normally at the display by web surfing or rummaging around the OS interface and I get a sense of less vibrance and saturation overall. It's the weirdest sensation I've never experienced in a display. I'm only concerned that this optical sensation is going to induce me to over saturate my Raw images while editing.
    This LG 27" was calibrated at the factory by a Minolta CA210 display spectrum analyzer and out of the box it shows a very neutral looking and uniform 21 step grayramp. The Colormunki Display reads default color temp at 6700K. A slight tweak to the RGB gains from 50,50,50 to 51,50,47 delivers a perfect by the numbers 6500K as read in Photoshop's Color Settings CustomRGB dialog box. Colormunki won't give CCT readouts after profiling like my original i1Display. I resorted to using Colorsync's vcgt graph to show how linear this display already is posted below.
    I wonder if the green/yellow extension in the 3D gamut model has something to do with affecting SPD's with white LED's because I've seen this same typical shape with my Samsung HDtv and other ICC profiles of other LED displays in this price range.
     
  27. dupe removed. Forgot to downsize graphic to 700 pixels
     
  28. Here's the graphic...
    00bjjW-540773684.jpg
     
  29. digitaldog

    digitaldog Andrew Rodney

    I think you're on to something there about the different backlight spectra.​
    I can't take any credit, it's all spelled out in this very interesting article on it's way to CIE for publication. I did email the author about when it may be released so you folks can read it and also see some very interesting visuals just in terms of the experiment in matching differing images with displays with differing spectra. That picture is worth 1000 words we've had here already.
     
  30. Hope you'll give us a heads up on that article when it gets released, Andrew. Very curious to see what they came up with especially the visuals.
     
  31. Andrew,
    My article is about matching the image on the monitor with the print illuminated by the digital darkroom lighting, side by side. It is not about viewing environments away from the digital darkroom, which is way less critical and leaves much room for personal preference. This distinction is very important to understand.
    You really haven't said if and how you achieve a match inside your digital darkroom. Do you use your SoLux 4700K and GTI fluorescent booth right next to your monitor?
    Let me try to answer your questions:
    "But the bottom lineis, suggesting a fixed value to set for display calibration without taking a number of important factors into consideration does more harm than good. Those factors have been presented to you more than once, I would ask you look them over and reply."
    "Based on both our understanding of just how the backlight of a display can alter the results, how can you say that everyone should calibrate to 5000K?"
    "Are you certain that every instrument used to calibrate a display, mated with all the various software products that have a setting for 5000K produce identical results?"
    "That the blackbody is a theoretical object and that yes, your mileage will vary, a lot and that simply expecting everyone to set 5000K and get a match is impossible. IF that were not the case, why is it that higher end systems like Eizo and NEC provide such precise control over differing white point settings? CCT Kelvin values in one value increments, the ability to enter chromaticity values, even the ability to measure with an instrument the viewing conditions? Why not have a single setting in such software products: 5000K? Because that one size fits all WP doesn't work for everyone, not even close."
    "There are Fluorescent bulbs ranging from $1 to far more that have 5000K on them. Do you believe they are identical and produce 5000K?"
    I recommend SoLux bulbs because they have the best spectrum to view prints. I recommend the same color temperature for the monitor and the lighting because color science suggests that would give the best match and in my experience that is indeed the case. So that leaves the question of which color temperature to use. I recommend 5000K because that is in my opinion the best compromise between the monitor being perceived by many as being to reddish and the light being too bluish; going lower than 5000K will make the monitor look even worse for many people and going higher simply isn't an option with SoLux.
    If you can stand a 4700K monitor, use the 4700K SoLux bulbs. I prefer 5000K and the SoLux 5000K bulbs last long enough for me.
    So what about the differences in calibrator accuracies, LCD panel backlighting, differences in light perception for different people, etc.? As long as you use a decent IPS monitor and calibrator and observe other good digital darkroom practices mentioned in my article, you should get a very good match by using my recommendations. For instance, decent IPS monitors like the NEC PA231W with CCFL backlighting and the NEC P232W with LED backlighting show average delta E values of 0.2 and 0.4 respectively after SpectraView calibration, so that gives you an idea of the impact of different backlighting methods.
    If a very good match isn't good enough, than you will have to tweak your setup. And don't get me started on using fluorescent bulbs to view prints. As a matter of fact, I recommend you replace your fluorescent booth with one equipped with SoLux bulbs.
    "Maybe you would consider sending the PDF to say Chris Murphy or Phil Brandfield at Solux."
    Both Phil Bradfield and Kevin McGuire of SoLux have read my article and like it. They liked it so much that the latest version and previous versions have been on the SoLux website for years. The link is directly to their site.
     
  32. digitaldog

    digitaldog Andrew Rodney

    My article is about matching the image on the monitor with the print illuminated by the digital darkroom lighting, side by side. It is not about viewing environments away from the digital darkroom...​
    Exactly what I'm talking about too!
    You really haven't said if and how you achieve a match inside your digital darkroom. Do you use your SoLux 4700K and GTI fluorescent booth right next to your monitor?​
    I do use both (not at the same time!) and I do get a very close match.
    I recommend SoLux bulbs because they have the best spectrum to view prints.​
    I fully agree.
    I recommend the same color temperature for the monitor and the lighting because color science suggests that would give the best match and in my experience that is indeed the case.​
    What color scientists? References please.
    So what about the differences in calibrator accuracies, LCD panel backlighting, differences in light perception for different people, etc.?​
    Yet you haven't answered the questions about differing products producing differing results with the same CCT value, the differences in how SPD's of various items in the chain affect viewer perception and have ignored the CIE piece that shows JUST the differences in backlight technology result in a whopping dE of 13! That's HUGE. How do you explain this?
    For instance, decent IPS monitors like the NEC PA231W with CCFL backlighting and the NEC P232W with LED backlighting show average delta E values of 0.2 and 0.4 respectively after SpectraView calibration​
    Meaningless measurement (and just how did you measure this)? You say you don't own a Spectrophotometer. Further, using the same device to measure something without a reference device known to be more accurate isn't at all useful. No matter how many times you measure the distance of your room with your foot, which may be 11 inches, you get the same results until you use a reference, a ruler to show your foot is not 12 inches.
    Both Phil Bradfield and Kevin McGuire of SoLux have read my article and like it.​
    I'm sure they like it, it mentions their product. Liking it and agreeing on the findings are two different things.
    Read this, it explains how and why one has to use differing values to produce a visual match and why one setting doesn't fit all. Further, you haven't explained any of the points above you quoted. Which is a tad telling. Anyway, here's how to get a match, it isn't about using some setting I recommend because everyone will need a differing setting (just to account for viewer metamerism failure)!
    http://www.luminous-landscape.com/tutorials/why_are_my_prints_too_dark.shtml
     
  33. Andrew,
    It looks like we totally agree on the need to match brightness between the monitor and print.
    "I do get a very close match": you still haven't said what your monitor is calibrated to when you use the SoLux bulbs and when you use the GTI fluorescent booth. Again, I would advise you to ditch the fluorescent booth for the reasons you mention yourself in your article.
    "What color scientists? References please.": if this isn't self-evident I don't know what is.
    "Yet you haven't answered the questions about...": yes I have. Read the answer!
    "...have ignored the CIE piece...": you want me to comment on a piece that I haven't seen? I gave an example of what different backlighting does to avg. delta E. Did the author let his subjects repeat the tweaking process at different times to get a feel for how much "noise" there is on the efforts of the same person doing the same, arguable very difficult, activity? Maybe that's more of a driver of the variability.
    "...and just how did you measure this...": ever read the reviews on tftcentral?
    "Read this...": I did, a long time ago. And that's the way you say you should go about it. And I say you don't have to go through this long-drawn out process to get very good results. One could argue that many people would get frustrated, mislead, or get totally lost if they tried to follow your process.
     
  34. digitaldog

    digitaldog Andrew Rodney

    It looks like we totally agree on the need to match brightness between the monitor and print.​
    Numerically, no. Visually, yes. Therefore, any canned recommendation for a cd/m2 is useless.
    "I do get a very close match": you still haven't said what your monitor is calibrated to when you use the SoLux bulbs and when you use the GTI fluorescent booth.​
    The NEC has multiple calibration targets based on viewing conditions and papers (I can control the display contrast ratio).
    Again, I would advise you to ditch the fluorescent booth for the reasons you mention yourself in your article.​
    It probably never occurred to you that we color professionals work with others in a collaborated fashion. Have you ever been in a prepress house or print shop? The vast majority use Fluorescent booths, almost always made by either GDI or Just Normalich. I have such a booth because I work with very high in print companies and we can't be ambiguous about how we view proofs. Why don't you try telling RR Donnelley they should ditch the hundreds of Fluorescent booth's?
    if this isn't self-evident I don't know what is.​
    I'll take that as a negative to having heard this from a so called color scientist. Unlike those who wrote the paper for the CIE I referenced.
    "Yet you haven't answered the questions about...": yes I have. Read the answer!​
    Where? Let me ask just one or two again so you don't go into overload:
    1. "Based on both our understanding of just how the backlight of a display can alter the results, how can you say that everyone should calibrate to 5000K?"
    2. "Are you certain that every instrument used to calibrate a display, mated with all the various software products that have a setting for 5000K produce identical results"?
    3. "There are Fluorescent bulbs ranging from $1 to far more that have 5000K on them. Do you believe they are identical and produce 5000K?"
    The only "answer" I see from you is: I recommend SoLux bulbs because they have the best spectrum to view prints.
    So yes, looks like you're ignoring the questions.
    you want me to comment on a piece that I haven't seen?​
    The premise is not sound? That the greatly differing SPD's of devices, something you touch on in your piece all match when set to 5000K? Oops, two more questions you can ignore.
    And I say you don't have to go through this long-drawn out process to get very good results.​
    No, I said one has to use trial and error to get a visual match, not ignoring the huge differences in the various devices, conditions and visual anomalies that make the idea that everyone should just select 5000K impossible to swallow. Otherwise every solution would fix and force a 5000K calibration which isn't the case one bit. In your mind that's the simplistic path: no matter the instrument and it's filters, no matter the display technology, no matter the surround and conditions, set the number to 5000K and you'll get a match.
    Frans, just how many sites have you gone to for setting up color management solutions? How many found that simply setting calibration to 5000K produced a visual match? Sorry, more questions. I don't expect answers. I do expect you to consider the 'advise' you are giving readers. Getting a print to screen match isn't rocket science, but it does take some effort after which, you simply continue to use the same systems. Replace one component something you might consider inconsequential like a display, you better test the process again. Sticking to 5000K, a value that is a large range of possible colors isn't the answer.
     
  35. It looks like we totally agree on the need to match brightness between the monitor and print.
    Numerically, no. Visually, yes. Therefore, any canned recommendation for a cd/m2 is useless.​
    Can I ask you both a question about this?
    Until now, I thought I understood the purpose of matching the monitor and print (in terms of brightness, white point, etc.)
    But suddenly I find myself wondering why we do things like set up print viewing booths with Solux lights, etc. I mean, after you're done with the print, nobody looks at it in nearly as perfect an environment, even in the nicest galleries.
    So why do we bother? I understand the point of calibrating one's monitor even when developing for web output, because while the web is a wild, uncontrolled place, at least it's as good as can be and will look good for the few viewers who actually do calibrate.
    But with prints, there isn't a single calibration standard, so there aren't even the few who do calibrate. So I'm suddenly lost on the point of calibrating for print matching. Help?
     
  36. Mark,
    You want your print, as viewed in the digital darkroom, to be as close as possible to the image on your monitor, otherwise editing becomes iffy. Suppose you have purplish flower on your screen, you print the image, and it turns out way to reddish to your liking. How would you then edit the image on your screen? Whatever you do to the monitor image will give you unpredictable results in print. That's why you want WYSIWYG, what you see (on the monitor) is what you get (in print).
     
  37. digitaldog

    digitaldog Andrew Rodney

    But suddenly I find myself wondering why we do things like set up print viewing booths with Solux lights, etc. I mean, after you're done with the print, nobody looks at it in nearly as perfect an environment, even in the nicest galleries.​
    Mark, I address this in my piece (why are my prints too dark) in the section: Moving the print.
    http://www.luminous-landscape.com/tutorials/why_are_my_prints_too_dark.shtml
     
  38. Andrew,
    "Numerically, no. Visually, yes. Therefore, any canned recommendation for a cd/m2 is useless.": nowhere do I recommend a certain cd/m^2.
    "The NEC has multiple calibration targets based on viewing conditions and papers": you are still not telling us what your monitor is calibrated to.
    "It probably never occurred to you...": yeah, I'm a dummy. Many wrongs don't make a right. And yes, I understand the implications, but somebody's got to speak out to do the right thing, maybe not right this minute, but unless you start thinking about what needs to change, nothing ever will.
    "I'll take that as a negative to having heard this from a so called color scientist. Unlike those who wrote the paper for the CIE I referenced.": yeah, I'm a dummy and I can't think for myself so I just make up things, even my own opinions. Somebody should make me stop doing that.
    "The only "answer" I see from you is: I recommend SoLux bulbs because they have the best spectrum to view prints. So yes, looks like you're ignoring the questions.": If you took the effort to really read what I'm saying, you would have seen that I said that all those issues are not big enough to prevent you from getting a very good match if you follow my advice.
    "...so you don't go into overload...": is such condescending really necessary?
    "The premise is not sound?": now you want me to comment on the premise of a piece I haven' seen? I didn't say they match, I said they are not big enough to make a visual difference for most people, unlike you of course.
    " Oops, two more questions you can ignore.": should I stop right here or are you interested in an honest discussion?
    Maybe keeping it simple is the answer for most people. Ever thought of that?
     
  39. digitaldog

    digitaldog Andrew Rodney

    nowhere do I recommend a certain cd/m^2.​
    I never said YOU do.
    you are still not telling us what your monitor is calibrated to.​
    What I use doesn't matter because YMMV. But in an effort to show you how questions can be specifically answered: ONE of my calibration targets is a WP of CCT 5750K using an EyeOne Display-2 on a PA271W, 150cd/m2 for a match to a GTI booth set digitally at for dimming at a value of 67 (something you can't do with Solux), Gamma 2.2, 300:1, Full Gamut. What you don't seem to grasp is that the beauty of the NEC design is the ability to produce any number of calibration targets (aim points) so that one can setup the display calibration to match a print! I have half a dozen different settings! That's why they built this functionality into the hardware and software.
    yeah, I'm a dummy.
    I'm a dummy and I can't think for myself so I just make up things, even my own opinions.​
    1st: You are entitled to your own opinions, not your own facts. 2nd: I initially thought you were interested in an conversation but with such text, I've come to the conclusion you're not and now you're wasting my time.
    I didn't say they match, I said they are not big enough to make a visual difference for most people, unlike you of course.​
    Another opinion without any facts to back it up. 1dE or less? That's not a visual difference. The article discusses between 3 and 13dE (76), the average for all users was a dE of 8 and that's huge, very visible.
    should I stop right here or are you interested in an honest discussion?​
    Yes considering your posts thus far and how you continue to ignore salient and clear questions about how you came up with your 'opinion'. Doesn't appear as yet to be fact based. As thus it's a waste of time for me as my original intent was to help you. Be honest, answer the questions presented to you fully or move on.
    Maybe keeping it simple is the answer for most people. Ever thought of that.​
    Simple and incorrect, not interested.
     
  40. digitaldog

    digitaldog Andrew Rodney

    Graphic artists who plan to print on offset presses may prefer to use 5000K, which is the ISO standard for the graphic arts. However, viewing standards were written for fluorescent light bulbs. CRT monitors are generally dimmer, especially when adjusted to match 5000K. Many users find that 5000K is too warm and dull and prefer to use higher settings like 5500 or 6500. LCD monitors can be brighter and can be calibrated to any value between 5000 and 6500 without diminishing the brightness, but we still recommend 6500K for general graphics use. Some advanced users try different values (always between 5000 and 6500) to find the one that best matches the look of their paper under their viewing conditions.
    http://www.xritephoto.com/documents/literature/en/DisplayProfilingNTK_EN.pdf
     
  41. Thanks, Andrew, but that didn't completely answer my question, though it leads me down the path. In the article, you write:
    Other than the rare problematic condition called metameric failure, often incorrectly called metamerism** if the print looked good under the viewing booth and matched the display, you will almost always find it looks good under other illuminants. ​
    Is the assumption that metameric failure is more likely to happen if you don't match the print to the monitor under a proper light booth? Does the white point of the monitor/booth affect the likelihood of metameric failure?
     
  42. digitaldog

    digitaldog Andrew Rodney

    Is the assumption that metameric failure is more likely to happen if you don't match the print to the monitor under a proper light booth?​
    Metameric failure is a condition where a print may appear a fixed way under one illuminate (neutral) but under another it appears to shift to green as an example. The causes can be due to the actual illuminate, the addition of OBA's (optical brighteners) in the paper interacting with the illuminate or both.
    Does the white point of the monitor/booth affect the likelihood of metameric failure?​
    Very possibly. Additionally there is the possibility of viewer (observer) metamerism which is the meat and potatoes of the CIE article I referenced. The effect of Observer metamerism is another reason why a 5000K calibration of a display and a 5000K viewing condition might produce a visual mismatch.
     
  43. Andrew,
    You wrote:"What I use doesn't matter because YMMV. But in an effort to show you how questions can be specifically answered: ONE of my calibration targets is a WP of CCT 5750K using an EyeOne Display-2 on a PA271W, 150cd/m2 for a match to a GTI booth set digitally at for dimming at a value of 67 (something you can't do with Solux), Gamma 2.2, 300:1, Full Gamut."
    Yes, a very specific, but incomplete answer and you should know it is incomplete given the context of my article, which is the subject of every objection that you have brought to bear here, paricularly my position that the color temperature of the monitor and lighting should match. So the obvious question, that you haven's answered yet, is: what is the color temperature of the GTI booth?
    Of course, all bets are off when you use fluorescents, as both you and I have alluded to in our respective articles. So, the more imortant question here is: what are the settings of the monitor when you use the SoLux lights and what is the color temp of those lights?
     
  44. digitaldog

    digitaldog Andrew Rodney

    So the obvious question, that you haven's answered yet, is: what is the color temperature of the GTI booth?
    Of course, all bets are off when you use fluorescents​
    First, you'll have to wait until next Thursday as all my equipment is off site as I'll be until then. Next, I can't understand why you'd want to know the color temp when you say all bets are off. But since I strive to answer all your questions, I will do so later next week when I and my Spectrophotometer's are in front of the GTI booth.
     
  45. Andrew,
    I'm more interested in your setup with the SoLux lights. Fluorescents never worked for me and given the horrendous peaks in their spectrum I don't know why anyone would want to work with them. I'm not sure what I could learn from your fluorescent setup numbers.
    Gerry Gerlach forwarded me Abjihit's paper on observer metamerism and I plan on making some observations after digesting the information.
     
  46. digitaldog

    digitaldog Andrew Rodney

    I'm more interested in your setup with the SoLux lights.​
    Then why did you write: what is the color temperature of the GTI booth?
    I've gone to great lengths to answer the questions you've asked me while you've answered hardly any IF any of my questions to you above (those have ? next to them). It's becoming progressively clear to me you have no intention or interest in an honest discussion (your words) but rather to attempt to grind down anyone who doesn't share your opinions. For example, in your last post:
    Fluorescents never worked for me and given the horrendous peaks in their spectrum I don't know why anyone would want to work with them.
    I told you why. I told you an advantage to such devices. I told you I agree about their spectrum.
    I'm not sure what I could learn from your fluorescent setup numbers.​
    So it's another Frans Waterlander who asked what is the color temperature of the GTI booth?
    YOU started this thread informing us of your new improved article. I read it. I wish you had written here: I've updated my article on digital darkroom lighting and please no comments other than positive, I have no interest in peer review and what I've written is technically excellent in every area. Had you said that, I'd have ignore you after post 1.
    Gerry Gerlach forwarded me Abjihit's paper on observer metamerism and I plan on making some observations after digesting the information.​
    If you can't even read the posts here and reply based on what's written, don't even attempt to digest Abjihit's paper, we have no hope of anything more than more digression from you.
    When I get back to the office with the Spectrophotometer, I'll measure both the Solux bulbs I use and the GTI booth if anything to illustrate how some people do strive to answer specific questions asked them. I'm without a doubt sure you'll either ignore the numbers or take us down another rabbit hole. You've illustrated in just the last 24 hours of your posts your ability to vacillate incessantly.
     
  47. Andrew,
    I thought I answered all your questions on page 4 of this thread, Jun 13, 2013, 04:09 p.m. I know you don't agree with them, but there they are. Do let me know if I missed any.
    From my perspective (match the color temp of monitor and lighting), the info you gave about the GTI booth setup was incomplete without the booth color temp, so I asked. And yes, the info on your GTI booth setup is not nearly as important to me as your setup with the SoLux lighting. Fluorescents are a no-no for me, but I do understand why you work with them and I did get it when you said they have the advantage of being dimmed. I get that.
    I think we can do without comments like "...don't even attempt to digest Abjihit's paper..."?
     
  48. This cnet review of the Dell U2410 doesn't suggest it's not an 8 bit panel but the descriptions of the visual anomalies indicates the reviewer must have gotten a bad "not so perfect" build version of this model in the review posted below...
    Static dithering in the shadows?! Pinkish hue in whites?!...​
    Cnet's review of the U2410 was apparently based on a rev A00 copy. Without a followup on a rev A01 copy.
    http://www.tftcentral.co.uk/news_archive/19.htm
    Dell Accidentally Leak Firmware Fix for U2410!
    The two main issues with the U2410 A00 revision (the initial release) seem to be:
    • Green and pink tinting and colour uniformity problems across the screen
    • Dithering artefacts especially visible in dark shades when using the sRGB or AdobeRGB preset modes
    Dell Returns and Replacements
    Leaked User Updatable Firmware! - Make your U2410 an A01
     
  49. digitaldog

    digitaldog Andrew Rodney

    I thought I answered all your questions on page 4​
    You didn't, you provided a small paragraph which doesn't answer any of the questions:
    I recommend SoLux bulbs because they have the best spectrum to view prints. I recommend the same color temperature for the monitor and the lighting because color science suggests that would give the best match and in my experience that is indeed the case.
    We agree on the smoother spectrum of Solux. That doesn't answer these questions:
    1. "Based on both our understanding of just how the backlight of a display can alter the results, how can you say that everyone should calibrate to 5000K?"
    2. "Are you certain that every instrument used to calibrate a display, mated with all the various software products that have a setting for 5000K produce identical results"?
    3. "There are Fluorescent bulbs ranging from $1 to far more that have 5000K on them. Do you believe they are identical and produce 5000K?"
    The 'answer' above doesn't even start to discuss question #2. You ignore question #3 by ignoring the use of any Fluorescent lights. You haven't measured your Solux bulbs. You haven't measured the display with a device independent of the software used to calibrate the display to prove it's even calibrated at 5000K. You ignore that multiple software products will report such values and produce a different value when measured again with an independent software product. You totally ignore the CIE article that discusses that just the backlight technology produces visually different results as high as dE 13. You seem to agree that differing spectrum's produce differing visual results as you will not accept any Fluorescent viewing condition, but some how, in your mind, that same difference in a display backlight doesn't count, always set the display for 5000K. If Fluorescent are so piss poor, what are we to take of the use of Fluorescent (and as well LED) as display backlight? With those spectrum you hate, the display is producing 5000K?
    From my perspective (match the color temp of monitor and lighting), the info you gave about the GTI booth setup was incomplete without the booth color temp, so I asked.​
    The bulbs ARE rated at D50 (which isn't 5000K). further, I can almost guarantee you they will not measure at 5000K. But you asked anyway. The Solux bulb may be rated at 5000K, they probably will not measure 5000K but since you have no tools to test this, you force the proof on me! You take a lot at face values expect any peer review which is notable. I wonder what you'll say when I report the CCT Kelvin values of the Solux, the WP of a display set to a fixed value and the value of the GTI booth.
    So what about the differences in calibrator accuracies, LCD panel backlighting, differences in light perception for different people, etc.? As long as you use a decent IPS monitor and calibrator and observe other good digital darkroom practices mentioned in my article, you should get a very good match by using my recommendations.​
    You should? And if you don't? Then don't use 5000K? I am supposed to take this as:
    When 5000K matches, use 5000K. Duh! Still without any independent measuring of either the illuminant or the display by yourself.
    I think we can do without comments like "...don't even attempt to digest Abjihit's paper..."?​
    You can't seem to digest what I ask, that paper is far, far more complicated but hopefully just the pictures will be enough for you to SEE that differing SPD's used in a backlight ALONE produce a hugely visible difference so how can you then say, set everything to 5000K? It's ridiculous.
     
  50. digitaldog

    digitaldog Andrew Rodney

    Yes, a very specific, but incomplete answer...​
    While I end up with a very non specific and incomplete answer. Telling.
     
  51. Andrew,
    Ok, I'll take one question at a time. Here goes...
    1. "Based on both our understanding of just how the backlight of a display can alter the results, how can you say that everyone should calibrate to 5000K?" Calibration reduces errors caused by differences in backlighting. I gave the example of two NEC LCD monitors, identical but for the backlighting, one being CCFL, the other LED; after SpectraView II calibration the delta E was less than 0.2 and 0.4; that's an undetectable difference.
    2. "Are you certain that every instrument used to calibrate a display, mated with all the various software products that have a setting for 5000K produce identical results?" Of course there will be differences, but I don't think that those differences will be large. I have measured, with a Minolta color temperature meter, the results of 4900K calibrations with two different versions of the Monaco EZColor calibrator and one ColorVision calibrator and all were within 50K, which is undetectable to the human eye. That was about 10 years ago. I would think that with ongoing improvements most calibrators nowadays would be at least that accurate.
    3. "There are Fluorescent bulbs ranging from $1 to far more that have 5000K on them. Do you believe they are identical and produce 5000K?" No, I don't believe that and that should have been very clear for you given what I have said about fluorescents. All bets are off with them and that's why I strong recommend not to use them.
    "You haven't measured your Solux bulbs." That's a bad assumption on your part. I have measured them with the same Minolta meter and they were within about 50K when measured within the circle of light they project, staying away from the fringe around the circle of light; in the fringe area they show a color temp much lower, as they do in the back, which is why you should buy the ones with black paint on the back or use closed fixtures.
    "You haven't measured the display with a device independent of the software used to calibrate the display to prove it's even calibrated at 5000K. You ignore that multiple software products will report such values and produce a different value when measured again with an independent software product." I've dispelled those above.
    "You totally ignore the CIE article that discusses that just the backlight technology produces visually different results as high as dE 13." I'm not ignoring the article. As I said before, proper calibration should bring the errors below the human visibility threshold. For starters, the article doesn't give any details about the monitors used or the calibration results like delta E. Further, it may be that the abysmal results in the article are caused by other factors like the viewing booth (I believe the article doesn't tell what booth was used: fluorescent, SoLux, LED?) or human error like repeatability: the article doesn't say whether or not tests were carried out to establish how repeatable the various test subjects could carry out the tasks. There are in my mind too many unanswered questions about that article after quickly scanning it (and yes, I will study it further and will let you and the author know) to just take it as fact.
    "If Fluorescent are so piss poor, what are we to take of the use of Fluorescent (and as well LED) as display backlight? With those spectrum you hate, the display is producing 5000K?" See above.
    "The bulbs ARE rated at D50 (which isn't 5000K). further, I can almost guarantee you they will not measure at 5000K. But you asked anyway. The Solux bulb may be rated at 5000K, they probably will not measure 5000K but since you have no tools to test this, you force the proof on me!" See above. And no, they are not and measure not 5000K; they are rated at 4900K and measure within 50K.
    "Still without any independent measuring of either the illuminant or the display by yourself." Again this assumption that I don't do my homework!
    "...but hopefully just the pictures will be enough for you..." Again Andrew, we could do without this uncalled for sarcasm or whatever it is that is eating at you.
    "While I end up with a very non specific and incomplete answer. Telling." Is this reply specific enough for you? I hope so.
     
  52. digitaldog

    digitaldog Andrew Rodney

    I gave the example of two NEC LCD monitors, identical but for the backlighting, one being CCFL, the other LED; after SpectraView II calibration the delta E was less than 0.2 and 0.4; that's an undetectable difference.​
    And I told you that methodology doesn’t wash, you used the same software and instrument to produce the results without using another reference device and independent software to test the output. I gave you an analogy of why this isn't acceptable! You can measure that room 1000 times with your 11 inch foot and the results will always be incorrect.
    Here are some interesting findings from a real color scientist from the ColorSync archives who also produces the product you could and should use for such testing. Notice the date and the impending release of the 5000K bulbs which predate your 'testing' with that old Minolta device you mention in 'answer' 2. Notice that two instruments were used and instruments that ARE suited for this kind of measurements:
    Subject: Re: Solux Bulb color temperature
    From: Robin Myers
    Date: Tue, 17 Feb 2009
    Here are the CCT results from measuring a Solux 4700K bulb, and two Solux 5000K bulbs (one with clear sides, one with black sides). The measurements were made 1 m from the front of the fixture to the measuring devices aperture.

    i1 Pro with Ambient filter

    Solux 4700 50W 36-degree 4304K +-4K
    Solux 5000 35 W 36-degree Clear 3974K +- 3K
    Solux 5000 35 W 36-degree Black 4428K +-7K
    PR-655 with CR-655 Cosine Corrector

    Solux 4700 50W 36-degree 4431K +-2K
    Solux 5000 35 W 36-degree Clear 4025K +- 4K
    Solux 5000 35 W 36-degree Black 4528K +-2K

    With only one sample each of the 5000K bulbs, it was not possible to double-check the 5000K Clear bulb, but it is apparent that the 5000K bulb is not right. I suspect it is a mismarked lower Kelvin bulb or a bad bulb.
    Otherwise, the i1 Pro and the PR-655 agree. There were two different setups, at two different locations but the light fixture was the same and the bulbs were the same for both sets of tests. The CCT was calculated with SpectraShop 3 (to be released later this week, hopefully) and the CCT results of 5 to 6 measurements of each bulb were averaged.
    The calculated CCTs do not agree with the expectation based on the manufacturer's marketing.
    In comparing the emission spectrums, the i1 Pro and PR-655 agree fairly well. Both of them have a general shape similar to the D50 curve, but much smoother. There are several small peaks in the D50 spectrum absent from the measured Solux spectra. The manufacturer has claimed a spectral shape similar to D50 and it is a reasonable approximation.
    In Ken Fleisher's original post, he reported a CCT of 4450K for the Solux 4700K bulbs and the results above agree with the lower than claimed CCT value (if you believe the "4700 Kelvin" on the bulb's box means CCT).

    Robin Myers​
    AR: "Are you certain that every instrument used to calibrate a display, mated with all the various software products that have a setting for 5000K produce identical results?"
    FW: Of course there will be differences, but I don't think that those differences will be large. I have measured, with a Minolta color temperature meter, the results of 4900K calibrations with two different versions of the Monaco EZColor calibrator and one ColorVision calibrator and all were within 50K, which is undetectable to the human eye. That was about 10 years ago. I would think that with ongoing improvements most calibrators nowadays would be at least that accurate.​
    The 10 year old Minolta was what device (a Spectrophotometer, Colorimeter) and it give you Lab or Spectral data? You don't think the differences will be large but you've not provided any metric to that assumption. Care to explain the results Robin found?
    That's enough as a start to your 'answers' which thus far are IMHO not based on sound methodology. Once we go farther, your 'answers' prove that your assumptions about calibration, profiling and matching differing devices fall apart even farther. But this is enough of a start, now that you've introduced more data for us to understand about your testing procedures.
    AR: "You haven't measured your Solux bulbs."
    That's a bad assumption on your part. I have measured them with the same Minolta meter and they were within about 50K
    I don't know how you measured the 5000K Solux bulbs 10 years ago when they were not in existence nor how your 50K difference differs so much from two others as outlined above. Care to explain?
     
  53. digitaldog

    digitaldog Andrew Rodney

    And there's this too from the list Franz:
    Subject: RE: Solux Bulb color temperature
    From: "Tim Vitale" <email@hidden>
    Date: Tue, 17 Feb 2009 11:21:24 -0800
    I have four Solux 4700 K 36deg floods that are about 1-2 years old
    with 100-300 hours (or so) on them. The only variation can be hours
    of use. I will be ordering a new batch quite soon. If you are still
    interested get back to me in 7-10 days and I'll report the newest
    findings.
    # 1 = 4363 K
    # 2 = 4550 K
    # 3 = 4307 K
    # 4 = 4456 K
    They were measured with an i1 Rev D (UV incl) in Emissive-Light mode,
    using Robin Myers SpectraShop.
    As Robin said earlier, I have never found a bulb to be the actual
    stated CCT. All except one.
    I just rebuilt my light bleaching set-up and purchased a $120, 250 W,
    Metal Halide "Hostile - Blue" lamp (Eye Lighting, Japan) that outputs
    6530 K +/- 35, with 16500 Lux, about 20" from the bulbs; less than 1
    hour old. As one would expect, it is a bit spiky, but not as bad as
    normal Metal Halide lamps. They label it 6500K in the PDF;
    http://www.eyehortilux.com/blue.html; PDF <EQS-N-52-78-57799[1].pdf>.
    Tim Vitale​
    All going back to my suggestion to ignore the numbers, they can be all over the place. The numbers for display WP calibration that produce a visual match are the correct numbers, they are rarely ever 5000K and that reported number is a range of colors anyway.
     
  54. digitaldog

    digitaldog Andrew Rodney

    AR: "The bulbs ARE rated at D50 (which isn't 5000K). further, I can almost guarantee you they will not measure at 5000K. But you asked anyway.The Solux bulb may be rated at 5000K, they probably will not measure 5000K but since you have no tools to test this, you force the proof on me!"
    See above. And no, they are not and measure not 5000K; they are rated at 4900K and measure within 50K.​
    Solux doesn't make a 4900K bulb. Never have.
    AR:"Still without any independent measuring of either the illuminant or the display by yourself."
    Again this assumption that I don't do my homework!​
    Yup!
    From the same ColorSync list:
    There are two bulbs rated at 4700K and
    5000K. We purchased the 5000K bulbs expecting the color temperature to be
    fairly close to this, but when we measured it we see it is 4450K. According
    to a Solux engineer, the term "D50" in their product literature refers to
    the spectral nature of the light, not the exact color temp as metered in
    Kelvin degrees, that the bulbs labeled 4700K produce a "daylight spectrum"
    and that they could be expected to rate within 200K of labeled output.​
    So again Fanz or anyone reading your piece, the numbers you hold so dear are not all that useful, you paid more for a bulb that doesn't last as long and bought into the marketing of having to have a Solux bulb that has 5000K written somewhere on it or the box (and which is really just the 4700K bulb in sheep's clothing).
    Between this and the CIE article, I'd say you probably should post to the ColorSync list your article and let the other color scientists comment.
     
  55. Andrew,
    Calibrators have a certain accuracy and when you know that you know what the possible errors in the CCT measurements are. I don't have this information at my fingertips, but for the sake of argument let's say it's +/- 5%. That would translate into +/- 250K for a 5000K calibration. That's not "all over the place" in my book. But since I don't know right now, I'll find out and report back.
    This really begs this question: since you claim that all bets are off, to paraphrase it, with monitor CCT numbers, you must have a pretty good idea how bad it is; can you share that information with us?
    Next, measuring SoLux CCT numbers. There are a lot of wrong ways to measure them and I'm pretty sure the two gentlemen you refer to are doing it wrong. SoLux has been faced with this issue for years and, as far as I can tell, have been able to prove the measurements wrong in each and every case they were able to get involved to sort out the mistakes made. An example is right on the SoLux website here: http://www.solux.net/cgi-bin/tlistore/infopages/ultralux-false-data.html
    After the measurement errors were corrected the 3500K measured at 3542K, the 4100K at 4194, and the 4700K at 4782, all within 100K.
    I dug out my notes from way back and here is the information. The Minolta I used was the Color Meter III F. I made the measurements 10 years ago in October of 2003 and I measured the 4700K versions, not the "5000K" version I said previously. I put the 5000K in quote marks because it is specified as 4900K.
    I measured the 4700K bulbs at between 4 and 7 feet and measured between 4690K and 4720K, well within the 50K I quoted previously. Getting into the fringe of the projected circle of light, letting the light escape from the back of the bulbs or letting other light, outside or otherwise, contaminate the meaurements shows up immediately in lower color temp readings, as my measurements clearly showed.
     
  56. digitaldog

    digitaldog Andrew Rodney

    Next, measuring SoLux CCT numbers. There are a lot of wrong ways to measure them and I'm pretty sure the two gentlemen you refer to are doing it wrong.​
    That's hilarious. Of course they are, you're not.
    Tell you what, put your money where your mouth is. Post to the ColorSync list the URL to your article, then ask the list if Robin's measuring is wrong. I dare you. I double dare you. You don't even own the proper equipment but a guy with a PR-655, and who wrote the software to drive it to measure this data is doing it wrong? Prove it.
    The Minolta I used was the Color Meter III F​
    Worthless for this task compared to a spectroradiometer and one of the quality of the PR-655, it runs about $13,000! You have the nerve to tell us you used this Minolta product to measure the values you want to see, but experts in color and color management software are doing it wrong?
    Come on, put up or shut up. Post the article or maybe I should? Ask Robin to comment on your testing methodology and tell him and the list, you're suggesting measured the bulbs wrong? They will have a field day with you!
     
  57. Andrew,
    "Solux doesn't make a 4900K bulb. Never have." What SoLux calls a 5000K actually runs at 4900K, as per their data sheet. Read it one of these days.
    "...and which is really just the 4700K bulb in sheep's clothing..." The "5000K" has, if I'm not mistaken, a 10V filament, which means it's overdriven at 12V, runs hotter and has a higher CCT. That's how these bulbs have different CCTs, by running them hotter or cooler.
    Did you read the article on the SoLux website I referred you to about the testing lab's mistakes and how the numbers came out after the measurement errors were corrected?
    If you want to pick a fight about SoLux bulbs, do it with SoLux. I'm sure they are in a way better position to defend the attacks on their products than me.
     
  58. digitaldog

    digitaldog Andrew Rodney

    OK, Frans, I'll address Solux off list, let's stick to your sloppy methodology and lack of proper test equipment that results in an article that you apparently can't (or will not) hold up to peer review. Let's see how it flies over on the CS list, when will you be posting the URL there as you did here? Or your rebuttal to the findings of the CIE article I was responsible for having sent to you that suggest an average dE of 8 which dismisses your concept that display and proofing condition that has the same CCT value always produce a match?
     
  59. Andrew,
    "OK, Frans, I'll address Solux off list": I'm sure that Phillip Bradfield or Kevin McGuire at SoLux will be happy to respond to Robin Meyers', Tim Vitale's and your assertions that SoLux bulbs are way, way off spec. Since you brought this up in this thread, however, you should report back here on this issue.
    "...let's stick to your sloppy methodology and lack of proper test equipment...": Tell me, if you please, what's so sloppy or improper about using a Minolta color temperature meter to measure 4700K with an accuracy of +/- 44K?
    And talking about putting up or shutting up (your words): let me repeat my previous request - how about you telling us how inaccurate CCT calibrations are; you keep repeating that those numbers are all over the place, so tell us how bad those are in your opinion?
    I'll keep working on getting accuracy information on calibrator accuracy and responding to the upcoming CIE article.
     
  60. digitaldog

    digitaldog Andrew Rodney

    Tell me, if you please, what's so sloppy or improper about using a Minolta color temperature meter to measure 4700K with an accuracy of +/- 44K?​
    I outlined your sloppy methodology TWICE along with an analogy you either didn't understand or decided like many of my posts to ignore. Now you want me to take on another digression of yours and explain why the device you used to measure the illuminate but not the display and which doesn't provide spectral data (despite your love of posting other's graphs of spectral data) doesn't wash. I wonder why you didn't use the Minolta device to read the CCT of the two displays?
    You asked me to measure my Solux bulbs but after providing you measurements from an actual color scientist with a $2K and $13K spectroradiometer and which closely correlates with another person running the same tests we are told: they did the measurements incorrectly. I'll indeed measure the Solux when I return from location but what's the point? If it doesn't match the values you want, you'll dismiss them as well. Mindset of a religious zealot who refuses to accept carbon dating and insist his Earth is 6000 years old.
    You've lost all credibility in my book, I suspect most other's still patient enough to read these last two dozen posts or so. You refuse to engage in any peer review. Hell will freeze over before you submit your paper to the ColorSync list, yet we poor PhotoNet readers have to put up with your lack of peer review paper and accept all your premises which makes me now realize I'm wasting my time debating not science but your religious belief of color. I'll not go down that path, you are free to believe any science fiction you wish. Why post it here?
    I'm off on location this week as I told you, I don't have any interest in going further until I see you post the URL of your article to the ColorSync list. Will take you no more than 5 minutes to do.
    You've had the CIE article that in the first two pages dismisses your ideas about color for days now, yet no reply which is telling. And like your dismal of Robin's measurements, you've already attempted to poke holes in it. I don't know how you sleep at night knowing you haven't as yet a leg to stand on here and that's why you'll never post your piece to the CS list or challenge Robin and the other's on their data. This from a guy who doesn't even own the correct equipment to make simple spectral measurements but will knock a guy who's been well know for years in the color industry and also happens to be mentioned on your beloved Solux web site (as am I).
    PhotoNet readers. Franz isn't to be taken seriously! He's got a some good points in his piece and some that are nonsense and he's got no means to back up his flat earth theories and as yet, hasn't posted his 'findings' to a peer review group like the CS list. Best to dismiss him as someone looking for a few free Solux bulbs or mention on the Solux web site. Reader beware.
    That's it bud. I'll post the CCT values Thursday if I get back on time since I promised to do so and nothing more. You'll suggest the data is wrong anyway. You'll never undergo the humiliation from the ColorSync group or challenge Robin on his data. And that says it all about your ability to write about a subject like color management.
     
  61. digitaldog

    digitaldog Andrew Rodney

    Not for Franz's eyes but useful data from CHROMIX the maker of ColorThink, Colorshuttle and Maxwell:
    Myth #16: Two 5000K bulbs will match
    -=-=-=-=-=-=-=-=
    First let's talk about 5000K, D50, D65, etc, how they are specified and what they describe.
    5000K is a color temperature. It's a color of white that is based on heating a "black body" object to 5000 Kelvin. When you get something this hot it glows a yellowish-white. This color is expressed as a colorimetric number, such as XYZ, Yxy or Lab and is then called a correlated color temperature. The lights that produce these colors of white are not actually burning at that temperature, they just make the same color of light as a black body that is - that's the correlation.
    D50, D65, etc are daylight illuminant standards based on spectral curves.
    Remember, spectral curves are the most detailed light information we can get. When we add human observer influence we get colorimetric numbers. An important thing to realize is that many different spectral curves can result in the same colorimetric number. Another way of putting this is to say that fluorescent, incandescent and sunlight can all have significantly different spectral output but still produce the same color of white for a human observer; the same colorimetric number.
    This "match" is for an even white card that has no brighteners. As each of these light sources have a different spectral make-up they will affect papers containing brighteners and printed colors differently.
    The net effect of this is that two bulbs that measure as 5000K can affect paper and printed color differently and that one print can look different under two 5000K bulbs.
    There is another measurement that reflects how closely a light source matches the D50 daylight spectral curve. CRI, the Color Rendering Index is expressed as a value out of 100. 100 is a perfect match to a reference light source that is within 100K temperature (D50 in the case of standard viewing environments). Typical cool white fluorescent bulbs have a CRI of about 62. The CIE states that the color differences between sources that differ by 3 CRI units is not perceptible. You should aim for CRIs that are as high as possible (over 95) when shopping for lighting and viewing products - and the booth can affect it as well.
    I suppose the summary point of this myth is that 5000K is not a guarantee that you have a good light source or that it will match another 5000K light source effectively.
    -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
    Myth #17: D50 bulbs are available
    http://www2.chromix.com/colorsmarts/smartNote.cxsa?snid=1112
    August 16th, 2004
    -=-=-=-=-=-=-=-=
    D50, as mentioned above, is a standard daylight spectral curve.
    This spectral information is defined very specifically using more than 30 curve points. It has a single colorimetric number and, unlike 5000K, it cannot be created by different light sources composed of different spectral output.
    D50 is so specific in fact, that the only thing that can create it is the sun as it passes through the Earth's atmosphere.
    Why choose a standard like D50 as an aim point if nothing man-made can achieve it? Well, because our visual system is based on millions of years of evolution under the sun. We are tuned to see objects illuminated by our star and filtered by our atmosphere.
    The light source that I have seen to be the closest to D50 is the Solux lamp designed by Tailored Lighting. It is a Halogen light that can be easily mounted in track-lighting systems and is also quite inexpensive (around $9 US per bulb). The Solux CRI is 98, the industry's best. You can find out more information about these bulbs from .
    If you are not interested in the more "do it yourself" side of lighting that track-lighting sometimes requires, consider GTI or Just Normlicht light boxes. They are fluorescent-based lighting systems which may not have as high a CRI but they are so widely used (especially GTI in the US) that they are de facto standards themselves. If you want to view things as many others view them, light booths will typically get you there.
    So, if a company is calling their lighting D50 I'd love to hear about it because it's probably not true. If they are calling it 5000K then they've chosen the broad side of a barn as their target. And if they quote a CRI they may be closer. At least they're more savvy. Remember D50 is the aim-point and so far Solux is the closest.​
     
  62. Andrew,
    Abusive language like you increasingly use has no place on this or any forum. That, coupled with your unwillingness to engage to the degree of actually responding to several of my questions, tells me that nothing constructive will come of this. I had my inputs for the CIE article ready to go, as well as answers about the accuracy of color temperature calibration of monitors and feedback on the measurements of SoLux bulbs, but I'll stop wasting my time.
    Please contact SoLux directly on the issue of their products meeting specifications. Their products have been proven to meet specifications every time that was challenged or misreported and every time setup errors were the cause of the faulty measurements.
     
  63. digitaldog

    digitaldog Andrew Rodney

    Apologies for abusive language.
    When will you be posting your article for review to the ColorSync list?
     
  64. Andrew,
    Apologies accepted. But I'll stop wasting my time nonetheless.
     
  65. digitaldog

    digitaldog Andrew Rodney

    But I'll stop wasting my time nonetheless.​
    Agreed although I will provide the Solux measurements as promised later this week.
    Final question: When will you be posting your article for review to the ColorSync list for review? Or maybe you could post on Luminous Landscape.
     
  66. Will I be posting my article for "review" on other forums? No thanks! I've had my fill for a while of insults and personal attacks.
     
  67. digitaldog

    digitaldog Andrew Rodney

    Will I be posting my article for "review" on other forums? No thanks! I've had my fill for a while of insults and personal attacks.​

    What makes you think the ColorSync list would do that Franz? Or are you just afraid of the findings of other 'peers'?
    No surprise, I didn't think you had the courage to subject your article to others and the reasons are clear. And I don't believe you'll let us know about the CIE article that pokes holes in your ideas. Best to ignore any discussions that don't agree with you, which is SO TELLING. I wonder what the other readers here who now know you will not subject your article to any review will think of it. As I said above, ignoring it would be their best move until you decide to let other's read and comment.

    What are you afraid of? Being proven you're wrong? Yup.
     
  68. Andrew,
    One has to seriously wonder about your apologies, given more insults and personal attacks. I'm all for an honest debate, but if you can't behave in a professional manner, than our "discussions" is over and done with. I wouldn't mind starting over with a clean slate, just let me know if you are sincerely interested in doing that, but I won't put up with any of your past behavior.
    I'll be more than happy to have a constructive dialog with anyone else.
     
  69. digitaldog

    digitaldog Andrew Rodney

    One has to seriously wonder about your apologies​
    I apologized for abusive language (your term) not for dismissing your premise or your poor methodology or your poor understanding of color management, or your continued efforts to say anyone disagreeing with your findings are wrong. Big difference!
    It's telling that you refuse to under go peer review on the CS list or elsewhere here. I suspect that no one else is following this discussion. I suspect few if any are accepting your article.
    IS anyone still here buying into Franz's concepts? Or wondering why he refuses to ask on the CS list about his piece and further, tell Robin Myers, a respected color scientist he's 'wrong' in using his equipment to come to the results he and at least two others came to?
    I'll be more than happy to have a constructive dialog with anyone else.​
    PROVE IT! Post the article to the CS list and ask for feedback! You know, it's up there for public digestion anyway, nothing stops someone from posting the URL and asking for comment. That toothpaste is out of the tube.
     
  70. Andrew,
    It looks like you are not willing to start over with a clean slate. You apparently don't want to take responsibility for your past abusive language by labeling it "your term". Then you continue to deride me with terms like poor methodology and poor understanding of color management. Sorry, that's not my definition of a clean slate.
    As for Robin Meyers and the others, tell me where best to bring up the subject of measuring SoLux bulb color temperatures with them and I'll do it, with the understanding that they then would take up the subject directly with SoLux, as they can best address the issue (as they have done numerous times in the past). I'm not their spokesperson or have the best possible information to address this issue.
     
  71. digitaldog

    digitaldog Andrew Rodney

    As for Robin Meyers and the others, tell me where best to bring up the subject of measuring SoLux bulb color temperatures with them and I'll do it, with the understanding that they then would take up the subject directly with SoLux, as they can best address the issue (as they have done numerous times in the past).​
    I told you, several times. The ColorSync list where the discussion has been discussed and referenced here several times.
     
  72. I don't know what "the ColorSync list" is. Can you give me a url?
     
  73. digitaldog

    digitaldog Andrew Rodney

    https://lists.apple.com/mailman/options/colorsync-users/
     
  74. It looks like you must be a member, but it nowhere says how to become one.
     
  75. digitaldog

    digitaldog Andrew Rodney

    It looks like you must be a member, but it nowhere says how to become one.​
    It's NO different from setting up to use THIS forum. Not difficult.
    If you are having trouble using the lists, please contact mailman@lists.apple.com.
     
  76. Andrew,
    The url you gave leads to a page where you cannot sign up as a member, you only can sign in or unsubscribe. Mail to mailman@list.apple.com is undeliverable. I'm stuck.
     
  77. digitaldog

    digitaldog Andrew Rodney

    I guess you have to be a color scientist?
    OR:
    https://lists.apple.com/mailman/listinfo/colorsync-users
    Subscribing to Colorsync-users
    Subscribe to Colorsync-users by filling out the following form. You will be sent email requesting confirmation, to prevent others from gratuitously subscribing you. This is a hidden list, which means that the list of members is available only to the list administrator.
     
  78. Andrew,
    You wrote: "I guess you have to be a color scientist?" I guess you can't help yourself making these kinds of jabs? One more and I'm out.
    Anyway, I registered and all I see is that I can send an email to the ColorSync users list. Then what? Are respondents going to email me back with their replies individually or is there a place like this forum where everybody who signed up can look at all the interactions?
     
  79. digitaldog

    digitaldog Andrew Rodney

    I registered and all I see is that I can send an email to the ColorSync users list. Then what?​
    You send email to the list! The list gets the emails. They reply. You get the email(s). You reply back. Haven't seen any email from you through the list.
     
  80. digitaldog

    digitaldog Andrew Rodney

    Using Colorsync-users
    To post a message to all the list members, send email to colorsync-users@lists.apple.com.
    You can subscribe to the list, or change your existing subscription, in the sections below.
    Additionally: IF you have more than one email address, you must use the one you signed up with. If you reply using another email address, (email host uses a differing one as default) it will bounce back.
     
  81. digitaldog

    digitaldog Andrew Rodney

    As promised (and mentioned in your new thread): Unit failed CCT:
    [​IMG]
    This is a 4700K bulb in a Solux lamp they themselves sell, not my own rig. So if you don't like the results and feel it's something to do with how the bulb is housed or installed, this is a 100% Solux solution with no other modifications.
     
  82. Andrew,
    Have you worked with Phillip Bradfield or Kevin McGuire at SoLux to resolve the issue and what was the result?
     
  83. digitaldog

    digitaldog Andrew Rodney

    Let's stick to one thread or the other, no need to repeat everything in two places. I addressed your needs for measurement data and I answered your last question the first time asked in that other post. There's nothing to resolve.
     
  84. digitaldog

    digitaldog Andrew Rodney

    I got an email from the author of the paper I referenced here that is for the CIE. The paper is up for public consumption at:
    http://www.abhijitsarkar.com/documents/Papers/SarkarBlonde_2013_Colorimetric-observer-categories_CIECentenaryConference.pdf
    It dismisses a lot of Franz's idea, the reason he hasn't replied back here after having had access to that paper for 10 days now. Abhijit has read Fran'z paper and had a number of issues with it and we are in agreement on his misunderstanding of D65 as a CRT legacy, gamma etc but no need to go much farther.
    Franz's ideas of 5000K for both print viewing and display can be easily dismissed in just the first two pages of this paper, something I originally posted on before Franz took us down this huge and unnecessary digression on Solux CCT ratings in two forum posts here on PhotoNet and over on LuLa.
     

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