Image file conversions from 5000K to 6500K

Discussion in 'Digital Darkroom' started by nino_loss, May 23, 2010.

  1. Hi,
    I would like to automatically (through a software...?) convert my image files from 5300K to 6500K, in order to use them for the Web and other desktop publishing. As I primarily work for print on inkjet, I prepare these images with my screen set to 5300K (measured my paper white under JUST 5000K), gamma 2.2 and 250cd/m2 luminosity to match the paper.
    Thanks a lot in advance for your thoughts on this.
     
  2. digitaldog

    digitaldog Andrew Rodney

    To answer your question, ACR or Lightroom would do this (the later quickly). WHY you’d want to do this is questionable. Also be aware that Kelvin values are a range of colors, not a single, specific color. So each app will treat the images differently and you’ll probably get differing image appearances than you desire. And images have nothing to do with the kelvin value you calibrate your display to. The display is totally independent of the images, the output devices etc. Just what are you hoping to do here?
     
  3. Andrew, thank you very much for you prompt reply. Please excuse me for being imprecise. Here is what I meant to ask:
    Once I finished my work on the file, which means I printed the image, I would like to continue to use it in (for me) new ways, which is the web and other on screen presentations.
    My setup, as mentioned, is 5000K, gamma 2.2 and 250cd/m2. Because I have an other screen, which is calibrated to 6500K, I observed that the image does not look the same at all, it is way to blue. I can take any image software and kind of 'soft-proof' from screen to screen, until they match, but that's fastidious additional work.
    So my question is, isn't there a quicker, more rational way of doing that, meaning, transporting my visual choices for hue, saturation, contrast etc. from a 5000K monitor to a 6500K monitor so that the two images should look identical (or at least close)?
    Thanks again
     
  4. 250 cd/m^2, really? And that matches your paper? That's unusually bright.
     
  5. If you had a color profile identical to sRGB except for having a 5300K white point, you could assign that profile to an image and then convert to sRGB using absolute colorimetric rendering intent. Really old versions of Photoshop could create such a profile, but I don't know of a good way to do that anymore. Perhaps I can create and post one.
    Unfortunately most color management seems to default to perceptual intent, which uses the output device’s white point. The white point of these converted images would therefore look too red for almost anybody with a monitor white point of less than 6500K (including your own).
    If not for both the perceptual intent default and near total lack of color management at all, it would be better to just embed the modified sRGB 5300K profile set to absolute colorimetric intent. While this is the correct way to do it, it will almost never work in practice.
     
  6. Mark, yes 250 sounds bright indeed, but it matches (measured and confirmed through eyeballing) my viewing booth dimmed almost 50%. I never paid attention to that, or better forgot about that, but you are right it is bright, and I don't know why it is so bright. It is not to the point of the question, though it might make things more difficult when I try to convert my image files for the Web, as a classic sRGB profile assumes far lower luminosity.
     
  7. Joe, I hear your advice with the embedded sRGB profile modified to 5300K with absolute color rendering intent. Just why wouldn't that work?
     
  8. digitaldog

    digitaldog Andrew Rodney

    Here is what I meant to ask:
    Once I finished my work on the file, which means I printed the image, I would like to continue to use it in (for me) new ways, which is the web and other on screen presentations.​
    This again has nothing to do with the kelvin values defined in a working space. In an ICC aware app, with whatever working space you have, it either looks good or doesn’t. If it does, fine. Then if you need to repropose it for another use or output, you convert to that output color space (ie Adobe RGB to myprinter RGB). If you want to convert for the web, you take whatever RGB working space you currently have, with no regard to the color temp (white point) and convert to sRGB.
    My setup, as mentioned, is 5000K, gamma 2.2 and 250cd/m2.​
    That’s the targets you calibrate your display to, based hopefully on the way you view your prints. It has zero to with the documents themselves. ICC aware applications divorce the display from the images you edit. That’s why we have RGB working spaces which are solely independent from the display calibration and profile.
    Because I have an other screen, which is calibrated to 6500K, I observed that the image does not look the same at all, it is way to blue.​
    Then change the targets for the display calibration. Naturally two displays, calibrated and profiled to differing white points will look different. But you don’t alter the documents to produce a match. You alter the target calibration of the display.
     
  9. Joe, I hear your advice with the embedded sRGB profile modified to 5300K with absolute color rendering intent. Just why wouldn't that work?​
    It would work if the file were opened in a color managed application that doesn't override the absolute colorimetric rendering intent in the embedded profile. Very few applications will meet both of those criteria.
     
  10. Andrew, thank you for the detailed observations.
    I hopefully, follow you now. That means that (I am repeating and paraphrasing, to be sure to understand)
    - I don't need the second display calibrated to whatever target settings I assume for my output (in this case the Web), I just continue to have all my targets set in a way that they look good to me (and match the paper)
    - the files that I selected for the web simply need to be to be transformed to the output color space, meaning sRGB.
    Now, just one follow-up question on this, and this is was led me into the mistake (I assume): Why do I than read that for Photo editing, with the main intent being on screen presentation, should have the editing display targets set to 6500K with a Gamma 2.2 ? Is it not because this colortemperature and gamma settings are (somehow?) closer to the sRGB colorspace, and that every conversion, be it from one color space to an other, deteriorates the image (posterising, clipping, etc.)?
     
  11. digitaldog

    digitaldog Andrew Rodney

    I don't need the second display calibrated to whatever target settings I assume for my output (in this case the Web), I just continue to have all my targets set in a way that they look good to me (and match the paper)​
    You can try. But unless both displays are very similar, don’t expect identical color appearance (especially true if one is a standard sRGB like display, the other an Adobe RGB like display). On Windows, depending on the flavor and app, dual display support can be iffy. Most use the 2nd display for palettes. For that usage, calibrating and profiling it seems more work than necessary.
    The web is not color managed unless you use one of two browsers. If you do, they will match on each display that has a profile, what you saw in Photoshop. Other browsers will not.
    the files that I selected for the web simply need to be to be transformed to the output color space, meaning sRGB.​
    Yes. Users that work with calibrated and profiled displays and ICC aware web browsers will see what you saw. Those who don’t will not.
    Why do I than read that for Photo editing, with the main intent being on screen presentation, should have the editing display targets set to 6500K with a Gamma 2.2 ?​
    Because some have to give you a guideline to start, even if your mileage may vary. In terms of TRC Gamma, 2.2 is a good setting as nearly all displays behave closely to this target. For white point, it all depends on the viewing conditions of the print. 6500K (better, D65 which isn’t the same) is a good starting point. But since we have no idea what the illuminant you are using to view your print is, how warm or cool it may be, that D65 setting may or may not match. Too cool? Use a lower setting (ie D60, D50). Adjust to taste. The only true D50 (or D65) Lightsource is 95 million miles from your display.
    Is it not because this colortemperature and gamma settings are (somehow?) closer to the sRGB colorspace, and that every conversion, be it from one color space to an other, deteriorates the image (posterising, clipping, etc.)?​
    No, because again, the RGB working space is a Quasi-Device Independent color space you edit your images in and is totally separate from how we calibrate our displays or our output devices (see:The Role of working spaces in Adobe applicaitons)
     
  12. Joe, I hear your advice with the embedded sRGB profile modified to 5300K with absolute color rendering intent. Just why wouldn't that work?​
    Actually this does work in Safari, but not Firefox or any other web browser I know of.
    I’m starting to like that idea because it is the right way to do what you want, but it still won’t work very often.
    This image is pure white with an embedded profile that is 5300K white point and absolute colorimetric rendering intent but otherwise like sRGB. It will probably look native white in everything but Safari. Programs like Photoshop may ask how to handle the embedded profile.
     
  13. Clicked too fast past the option to attach an image.
    00WWgZ-246543584.jpg
     
  14. Andrew,
    I have my JUST 5000K viewing booth and ambient light. But let's say somebody wants to set up a darkroom from scratch. I have read quite some times, that when editing photographic images, people should set their screens to 6500K and their viewing conditions also. Why should that be better than setting the target to 5000K and using a 5000K viewing booth?
     
  15. Joe, thank you!
    That's very interesting. Unfortunately, as you say, it does not work.
     
  16. I would like to automatically (through a software...?) convert my image files from 5300K to 6500K, in order to use them for the Web and other desktop publishing. As I primarily work for print on inkjet, I prepare these images with my screen set to 5300K (measured my paper white under JUST 5000K), gamma 2.2 and 250cd/m2 luminosity to match the paper.​
    sRGB color space is D65 white point.
    Image color space has nothing to do with monitor color space.
    For example:
    1- if your image color space is sRGB or Adobe 1998, the white point is D65
    2- if your image color space is ProPhoto, the white point is D50
    3- and so on ......
    For web publishing a transform to sRGB (if image is not in sRGB) must be performed, this transform compensate for any original white point. This is what color management do.
     
  17. that's a clear answer Jacopo!
    As image color space has nothing to do with monitor color space, why is it, that according to what I understood till now, preferable to work in light close to D65 when working for the Web, close to "native" white point of the sRGB and Adobe 1998 color spaces?
     
  18. digitaldog

    digitaldog Andrew Rodney

    I have my JUST 5000K viewing booth and ambient light. But let's say somebody wants to set up a darkroom from scratch. I have read quite some times, that when editing photographic images, people should set their screens to 6500K and their viewing conditions also. Why should that be better than setting the target to 5000K and using a 5000K viewing booth?​
    Got to get past the numbers. They are often meaningless or at least Your Mileage May Vary. In the old days, people figured they had 5000K viewing booths (mostly Fluorescent) so it made sense to calibrate their CRTs to 5000K too. Problem is, they got a dim, yellow appearing display. The numbers didn’t work. 6500K did. But again, YMMV. You might calibrate to D55, D65, even calibrate to a custom set of X/Y chromaticity values which some products let you do. The numbers are only correct when you get a match! Since the viewing conditions are often undefined, and since different products claim to be this or that kelvin value (keeping in mind a kelvin value is a range of colors), no wonder people who expect exact numbers to produce a match are disappointed.
    IF you could heat your display to 5000K, and it behaved like a theoretical black body radiator, you’d get a match and a pool of molten plastic on your desktop.
     
  19. So, to resume, back to my original question, which I would like to try to ask differently now:
    When converting image files for the Web, should there be a difference regarding Hue, Contrast, Saturation... between an image file produced in my work flow, entirely close to D50 (Sensor, Strobes, ProPhoto, Monitor, Light booth, ambient light...) to an image file edited in a setup closer to D65 (and assume I would be comfortable with both setups)?
     
  20. preferable to work in light close to D65 when working for the Web, close to "native" white point of the sRGB and Adobe 1998 color spaces?​
    You have to work with a monitor white point that is "comfortable".
    For people "comfortable" means 6000/6500K (near D65).
    This is true not only for web.
     
  21. I do not understand why you assume that
    For people "comfortable" means 6000/6500K (near D65).
    This is true not only for web.​
    For me I work in a 5000/5500 (near D50) environment, my eyes adapt and white is white (well screen to print is a different story). I think it is relative. Proof is that when I am, which happens to me, in a 6000/6500 (near D65) environment I also find it perfectly acceptable after adaptation. The problem of preferring D65 over D50 or D55, or the other way round, only arises for me when confronted with a white point different from that of the rest of the environment to which my eyes already adapted.
     
  22. Generally near D50 is peceived as yellowish, as the chromatic adaptation is not complete.
    But if you are satisfied, you can stay with your values.
    I that case, remember to look at web images using a color managed browser.
    This is a good suggestion in any case.
     
  23. BTW on the Solux Web site you can find their account of the tests they did to find out under which color temperature people really prefer to look at reflective images, in this case art work in a museum. 3500K that is. This preference does evidently say nothing about the fact, whether those people experienced white as white, which is what we discuss here.
     
  24. Jacopo, could you direct me to more information about that last point you made, about the fact that chromatic adaptation in not complete near D50? You are saying that chromatic adaptation to monitor target value of 6500K or 6000K is better in that respect?
     
  25. The concept that chromatic adaptation is incomplete is a general concept. Not only near D50.
    Human visual system is able to discount the illuminant, but the discount is not perfect.
    A white shirt is "white" under very different illuminants.
    But colors at sunset/sunrise are very different from colors at noon.
    The reason for D65 white is "more" white than D50 white is the same reason for wich in many
    detergents for washing machine blue components are added and the same reason for wich oba
    (optical brightner additives) are used for some printing paper.
     
  26. In the practical work of real life printing for the public; folks view prints; cereal boxes; beer cartons; newspapers, books under all sorts of lighting types.
    The typical web user surfing the web does not have a calibrated monitor.
    One out of ten men are color blind.
    The typical super white paper folks view as the holy best has brighteners and the brighteners poop up with exposure to light.
    Old folks have cataracts; they often see less blues and want goosed saturation so a print looks normal to them.
    ****Nino; it is not really clear by your several current threads if you are:
    (A) going into the printing business or
    (B)going into the calibration business;
    (C)or writing a book or teaching; or
    (D) just printing in house or at your home
    *****When dealing with other's inputs; there can be a mess of uncontrolled stuff ; two or three orders of magnitude worse. One has egos, gobble gook instead of a controlled input.
    (1)About the only place folks display prints under reference conditions is a Museum or a photo Gallery.
    (2) If you are going into the printing business then you have to deal with the public who: Does not know is who Kelvin is. Their monitor is not calibrated; they bring in Jpegs. What you print will be viewed under a mix of Kitchen and Bath lamps LED's; Edison bulbs and window light.
    (3) as a practical matter the reference that a real live customer wants for that 24x36" poster is a school Jersey. The input is a Jpeg; WB set wrong; the shot from a School Gym that due to the poor economy has a mix of vapor lamp types and edison bulbs, ie one has a light source that is not a perfect blackbody radiator; it is a notchy spectrum with spikes; a big miss-mash. Thus in the real world of dealing with a live paying customer; Kelvin, color space, white point,gamma, profiles, palettes, luminosity mean *ZER0*. What matters is me as printer forcing the images to be as close as possible to the Kid's Jersey.
    (4) customers who know some about "Kelvin, color space, white point,gamma, profiles, palettes, luminosity " tend to be worse; there is no Jersey and their calibration scheme has some flaws; major once and thus one has a circular mess. One can as a printer have everything dialed in an calibrated and your set up is declared wrong if their prints do not look OK.
    (5) a tiny fraction of folks know what they are doing and have a calibrated settup.
    Thus one best customers know very little (3) or extremely a lot. (5) The vast middle group of customers (4) with a tad of knowledges often know enough to be dangerous; thus this group causes scrap; reprints; explaining; often 5 times the labor cost per print.
    It is not really clear what the purpose is for your concerns. If your client is Beer label; they may not know Kelvin from RGBl but know if their label looks off color or hue. A HUGE amount of folks is like this.
     
  27. BTW on the Solux Web site you can find their account of the tests they did to find out under which color temperature people really prefer to look at reflective images, in this case art work in a museum. 3500K that is. This preference does evidently say nothing about the fact, whether those people experienced white as white, which is what we discuss here.​
    May be the light in the museum was about 3500K. And people like to see about the same colors.
    If you shot a photo at a sunset, do you like to see a print that reflects the sunset colors?
    To get the sunset colors the image colors are to be "sunset colors". You have not to change the monitor temperature.
     
  28. digitaldog

    digitaldog Andrew Rodney

    (1)About the only place folks display prints under reference conditions is a Museum or a photo Gallery.​
    Or the number of photo studios and prepress sites that have a clue about color management.
    (4) customers who know some about "Kelvin, color space, white point,gamma, profiles, palettes, luminosity " tend to be worse;​
    Yup, in your universe, ignorance is bliss (in terms of customers).
    (5) a tiny fraction of folks know what they are doing and have a calibrated settup.​
    Your customers or those photographers who strive to understand how their tools and techniques work?
     
  29. Kelly,
    I am "just" printing in house for my portrait studio. The quasi totality of my clients has so called 6500K or 3500K fluorescent or compact fluorescent tubes and absolutely no idea about computers or photography. But they have quite good eyes.
    I want to start to use more on screen presentations, CD, DVDs and the Web, especially for my "fine art" work. For that reason I had some old question coming up mixed to some new ones.
    I am "just" one of those photographers who strive to understand how their tools and techniques work, as Andrew puts it.
     
  30. digitaldog

    digitaldog Andrew Rodney

    The quasi totality of my clients has so called 6500K or 3500K fluorescent or compact fluorescent tubes and absolutely no idea about computers or photography. But they have quite good eyes.​
    They should be fine with what you hand them. Fortunately our visual system has white adaptation which you pointed out. The area where you want to nail so to speak, a white point match is when you are working with a display and a print viewing station next to the print. You want a visual match. One would expect that if the CCT Kelvin values are the same, they match. That doesn’t necessarily happen. CCT being Correlated Color Temp (the key word being correlated). Again, the right values are those that produce a visual match of these two quite differing ways of viewing an image.
    IF you get a good match and the output is as you desire, you can move that print to most other illuminants, your eye adapts to the white and you tell yourself that what you are now viewing matches what you say under the print booth and display. Since both are out of the equation at this point, and running from room A to room B to examine if they are a match is impossible, all that matters is that you are happy with the print under the current illuminant which 99 times out of 100, you will.
    As to Solux, they are awesome. Its about the best, affordable man made daylight simulation you can get. And yes, the CCT values are what they are, they don’t have to match what you think the numbers should be. When I was teaching a workshop for Photographer Art Wolfe in his gallery/studio/classroom, all his images in the galley were illuminated with off the shelf MR16 bulbs. We installed several Solux in the fixtures and he vastly preferred the 3500K to the higher rated bulbs even though they are supposed to correlate closer to daylight. Again, the numbers should not be taken literally.
     
  31. The quasi totality of my clients has so called 6500K or 3500K fluorescent or compact fluorescent tubes and absolutely no idea about computers or photography. But they have quite good eyes.​
    They should be fine with what you hand them. Fortunately our visual system has white adaptation which you pointed out.​
    but now I would like to send my work, lets call it "fine art", to people that will exclusively judge them on screen, before eventually showing them in a classic gallery setup(with 3500K Solux bulbs, which I also prefer)! Will they also be fine with what I hand them?
     
  32. Andrew;
    Yes; here I deal as a printer with the *entire Universe*; and you deal with a subset of it!
    Here the real world is dealing with actual clients with a zoo of lighting types ; but yours maybe calibration for subset of lighting types ; the easy ones that fit your simple models of perfect clients with pure daylight black body light sources; clients with 1000 years worth of digital experience and perfect inputs.
    Your narrower world is easier; you cherry pick the easy clients who have prints displayed under lab conditions. You are in the safe cocoon of a best case world.
    Real life printing is like plumbing; we get crap to deal with too.
    In the real world of printing folks want prints to be displayed under *THEIR* lighting conditions; not the textbook best case
    reference room at our shop with a about perfect voltage regulated blackbody source.
    The full Universe has more gotchyas than a calibration scheme for a known black body source.
    We printers often do NOT even know the viewing conditions; we have to ask; see; check.
    The color cal room we have has all the standard lamps; plus all those non standard lamps we printers use to please an actual client. In the real world all your cal stuff does *NOT* often matter in many jobs; we have some clients that demand great colors under *THEIR* jackass ill mixed lighting; thus we have the tools here to "close the loop around" mixed lighting; our matching room allow mixtures; just like the target clients viewing area. In the real world of printing; it is many times not the best case lab lighting; is a dream; not reality.
    Here I have a set up for viewing prints under all sorts of light types. There are lamp types of all the common 6 to 10 types Flourescent; edisons that we can adjust on a variac ; halogens; shop lights from walmart; museum quality bulbs. Its earliest stuff goes back to 1954; thus dealing with lamp types is old here; maybe before you were born even. I added some LED type lamps a casino customer uses to use this a clients reference; ie where the actual print are. When a client has wonky lighting; we have the tools to check prints under the *same type lighting.*
    We actually visit the clients target area with color temp meters; notepad; incident exposure meters; watt meters; tape measure. The clients target area might be a dark Las Vegas bar with LED lamps and warm red lamps and a mess others. Sometimes we can change their lighting; often not.
    A lot of this matching really is not the college sterile narrow perfect best case viewing conditions preached by calibration folks; it is radically more involved; radically more messy. You are pleasing a live fickle human being; not some color set of patches. Your might be pleasing a darn committee of folks. The real world has few sterile perfect blackbodies as light sources in bars; lounges; casinos; lobbies, boardrooms; it is a mixture; often an ill mixed one.
    ****Thus the client's print is made to look best as possible under *their* lighting conditions; ie NON perfect; NON cal lab.
    In the real world folks want their prints to look good under *THEIR* lighting; which is often not a blackbody radiator. Your acidic comments points to a lack of field experience in dealing with real customers by negative remarks. Your need to get some grit under your fingernails and walk out of the perfect bubble shell dream textbook world and deal with clients who want great prints under wonky ill lighting. It is a TOTALLY different world; like comparing a college controlled easy teaching medical exam to a war's Mash unit with a big mess of blood and guts. It is different in the trenches than best case easy stuff.
    ****What looks best under lab conditions can look poorer under the clients weird lighting; and most do not want their lighting changed at all.
    Clients really do not care a rats rear about perfect best case calibration theories; they want *good as possible* results down in the trenches; their area where the print goes. Your have to be open minded and LISTEN to the client's requirements; I am not sure if you are open minded enough to deal with clients who demand a great print under Kitchen and Bath bulbs; weird LED's or arc vapor lamps on a ballfield. It is more involved that sterile textbook lab conditions; one is making the print look best under their lighting.
    ***With a wonky lighting situation the loop is closed around not the armchair quarterback's sterile best case easy stuff; but a horrible mix; the clients actual lighting.
    We often get clients who are turned off by others lack of real world experience. ie those who are cocky and do not listen and are green. Your attack shows ignorance too; ie no real gritty world of real customers NON perfect lighting; it comes off as immature. Strive to get some more real world experience; the arm chair quarterback comments shows you rarely deal with imperfect lighting or customers.
    Do you actually deal with any customers; or is it just preach best case how to calibrate for the museum?
    A whole bunch of the lay public does not even know what light type they have; thus in real life printing one has a rubber reference; the clients often wonky miss mash of lighting types. Thus if their print looks great under the sterile perfect lab reference at out shop; it can not look as good under their wonky mixed lighting.
    Andrew; the whole world is not a perfect one of best case lighting; it often is a mix; sometimes a poor one.
    Thus a Beer client WANTS the beer carton too look great under poor store lighting and beer cooler lighting. This matters *MORE* than the serile perfect black body lighting. Few folks buy beer in print shops calibration rooms; or light reference rooms. Thus products that are sold under lighting type K with Klingon bulbs are made to look good under this lighting type.
    A gain of some real world printing experience will show you that folks want their prints to look good under the lighting type they are going to have their print or poster on display. It is a bit ignorant and cocky to just blindly assume that all clients are in a narrow cherry picked subset of the Full Universe of lighting mixes. Get your fingers dirty with a real world client; outside of the bubble. In the real world pleasing clients as very little to do with the sterile best case conditions of your calibration dogma; it is closing the loop around a great print in dark bar over a piano with ill lighting of which one has no control; with an image that is bloaded; has the levels set wrong .
    Thus we have the differences in those who teach and those who work in the field; a radically different thing. The whole Universe is what we printers deal with; not a narrow bubble.
    Here I shot 50 years ago with Kodak color references. In that era too the goal was to please the client and not get wrapped up in a tar baby or ball. Get some field experience. The world is not about calibration; it is about making the print look good to the client
     
  33. digitaldog

    digitaldog Andrew Rodney

    Yes; here I deal as a printer with the *entire Universe*; and you deal with a subset of it!​
    Ah, if you say so bud. The entire universe. And you can still find to post such lengthy verse here.
    Here the real world is dealing with actual clients with a zoo of lighting types​
    Doesn’t matter too much. White adaptation is a wonderful feature of our visual system.
    Your narrower world is easier; you cherry pick the easy clients who have prints displayed under lab conditions.​
    If you say so. Once I cherry pick these easy clients, its often useful to educate them to best practices instead of assuming they are just a bunch of clueless idiots. Makes them easier clients to deal with. You should try that sometime.
    We actually visit the clients target area with color temp meters;​
    If you’re not getting spectral data, just using something like a Minolta Color Meter, you’re chasing your tail. If you can’t see the SPD, where there are spikes in the spectrum of which every Fluorescent light produces, you’re not seeing the full picture here. But if it makes you and your clients feel better, so be it.
    We often get clients who are turned off by others lack of real world experience. ie those who are cocky and do not listen and are green. Your attack shows ignorance too; ie no real gritty world of real customers NON perfect lighting; it comes off as immature.​
    IF you say so bud (pot calling the kettle black).
    Do you actually deal with any customers; or is it just preach best case how to calibrate for the museum?​
    Do you really want to know?
    In the real world folks want their prints to look good under *THEIR* lighting; which is often not a blackbody radiator.​
    Actually it never is but go on...
    So pray tell, just what printing company are you representing, just in case I need to get output with all the sophisticated, real world, full universe experience you preach?
     
  34. Hey, I didn't read this whole thing, but 6000 Kelvin is a common default setting for monitors. Some print papers are bleached to that point. If you are doing pro-quality printing, coordinate with your printer. J.
     
  35. Wow! Kelly's Universe of Color Hell. What a workflow!
    I've got about five different light sources in my studio I view inkjet and a number of professional commercial press prints under and don't see a need to edit the digital files to correct for any light induced mismatches. I've got three clear globe incandescent bulbs over a vanity mirror, candelabra incandescent bulbs on my ceiling fan, a 5500K Ottlight CFL, a 4700K/D50 Solux, 5000K GE Sunshine fluorescent tube, Philips SP40 fluorescent tubes in my kitchen and soft white CFL's in my bathroom.
    The only way I can see a difference is to examine there affect viewing an X-rite CCchart target where the red, yellow and caucasian skin tone patches shift slightly in hue but more so in luminosity. Prints (photographs) only have an overall reduction in saturation and luminosity along with the noticeable color cast change.
    Kelly, if you've got clientele that seem so ignorant of lighting but picky as hell with the way color looks on their prints under their light source, I hope you're charging plenty for the editing sessions to compensate for something THEY THINK THEY'RE SEEING. Remember color is an emotional experience more so than a perceptual one.
    Otherwise you're working under a nightmarish and unrealistic business model that doesn't seem like it's worth the trouble or even profitable if you aren't charging for this closed loop custom color workflow.
    Maybe what you're really correcting for is metamerism's effect on different papers and ink sets. That sounds more realistic. I can see editing more magenta into a flat red graphic fill that looks orange under a particular light on some big ass poster or signage, but to correct the look of a wide range of colors in a photograph doesn't seem practical or necessary.
    Seems to me you're not letting the technology do the work for you or you don't know how to harness its potential. I have no idea, but there's no way in hell I'ld work at your facility with clients that picky and ignorant.
    Below is a demonstration using the CCchart showing the level of color shifts that are encountered under 2800K incandescent bulbs and correcting for them using technology (in this case a dual illuminant-2800K-6500K color table based custom profile as opposed to a single 6500K table).
    This is primarily to show the extent of the kind of color shifts that can happen and how fast you can correct for them which isn't as extreme as Kelly seems to indicate. Most folks would be happy with all four versions but THEY HAVE TO HAVE ALL FOUR VERSIONS TOGETHER TO NOTICE A DIFFERENCE AND THAT DOESN'T HAPPEN IN THE REAL WORLD.
    IOW, Kelly, I don't think you're telling the whole story. Everything I've learned from reading up on color science and human perception I see being accounted for and improved upon through color management technology. You just have to know how to use it and know its limitations.
    00WXNd-246885584.jpg
     
  36. Yes, there IS a big difference in image appearance on displays calibrated to different white point. I am working in printhouse prepress and in my own graphic design studio so almost all my and my customers displays are calibrated to 5000°K and everybody is happy watching right colors runnig out of the press.
    But sometimes I need same images to publish online too. I work primarily in ProPhoto RGB (which is D50) or Adobe RGB (which is D65) and then Save for the Web with sRGB profile (D65). Everything right isn't it? But here I get same problem: on 6500°K displays images look very cold. And vice versa some client that are printing at home and publish online having their displays calibrated to 6500K starting with commercial printing can't believe operator is sane and press is ok.

    I didn't found an automatic solution for this, so I just warn my clients on this issue. When I work on my images I just keep in mind to make them warmer on 5000°K display or colder on 6500°K, and I check them on my notebook (6500°K) before publishing online. If I ever need to "convert" many images from one white point to another I will probably create curves and apply it with Action.
     
  37. Google "Color Constancy". If you don't understand what the links you find are saying, then there's no point in continuing this discussion.
    Good luck with your current workflow.
    Life's too short to have to work that hard.
     
  38. To Tim Lookingbill: I know what is "Color Constancy". This theory work well in natural light, but here we are talking about displays and artificial lightning. In fact there is to big difference between D50 and D65.
    Calibrate your display to 6500K and look at the same image printed on perfectly calibrated printer in incandescent or just warm white lightning. Didn't you see any difference?
    Some images look ok in different lightning, others not.
     

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