sRGB vs Adobe RGB vs ProPhotoRGB

<p>What is the difference between the three working spaces. Is it just the gamut of color that varies with each working space or is it beyond that?</p>

<p>The main difference is the Gamut of color, being sRGB the smaller, then Adobe RGB and finally ProphotoRGB the largest.</p>

<p>Other differences:</p>

<p>Gamma: sRGB and AdobeRGB = 2.2 ; ProPhotoRGB = 1.8</p>

<p>White reference: sRGB and AdobeRGB = D65 ; ProPhotoRGB = D50</p>

<p>And, probably the most important one:</p>

<p>sRGB and AdobeRGB are based on VISIBLE primaries, which means that are real spaces so real devices like monitors can be made to show it. On the other hand, the primaries of ProphotoRGB cannot be seen, they are outside the visible color gamut for the human eye, so there will never be a device that shows this color space.</p>

<p>While it is true that its full colour gamut can't be displayed on a monitor, it is still the recommended colour space for editing your images (=working space) since it is the widest of the three spaces. Besides you wouldn't want to limit your images' colour gamut to what your monitor is able to render, since there are for instance printers that can reproduce colours that exceed the monitor's gamut.</p>

<p>Properly set up colour management will ensure that this large colour space is correctly translated into the smaller colour spaces of your monitor, printer etc.</p>

<p>Martin, I agree 100% with your post. I was just stating the specific differences between the color spaces.</p>

<p>Anyway, there are some issues to consider:</p>

<p>- It is recommended to use 16 bit per channel/color when using ProPhotoRGB (no JPGs)</p>

<p>- Converting between working profiles (i.e. from ProPhotoRGB to AdobeRGB) can only be done using relative colorimetric rendering intent (because there is no perceptual intent in matrix profiles, at least in V2 profiles) so special care has to be made for any color that is out of the gamut of the destination profile.</p>

<p>Hi Francisco, I didn't mean to disagree with you either. Just thought I'd mention, why it's best to stay in a wide gamut colour space such as ProPhotoRGB as your working space.</p>

<p>Does it make any difference when going from sRGB or Adobe RGB on the monitor to print-out (mine is a Photosmart B9180?)" I presume Adobe RGB is better, or is it? </p>

<p>I didn't know ProPhoto was 1.8 and D50. Does this imply we should calibrate our monitors with those parameters? It doesn't seem to make sense. I calibrate with 2.2 and D65, use ProPhoto and have no issues printing.</p>

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<p>Does it make any difference when going from sRGB or Adobe RGB on the monitor to print-out (mine is a Photosmart B9180?)" I presume Adobe RGB is better, or is it?</p>

 

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<p>AdobeRGB will have advantages especially with greens and cyans. At high luminances it has also advantages in magentas oranges and yellows</p>

<p>There is a good tutorial <a href="http://www.cambridgeincolour.com/tutorials/sRGB-AdobeRGB1998.htm">here</a></p>

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<p>I didn't know ProPhoto was 1.8 and D50. Does this imply we should calibrate our monitors with those parameters? It doesn't seem to make sense. I calibrate with 2.2 and D65, use ProPhoto and have no issues printing.</p>

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<p>Don't worry about that. Color management takes care of it. In any case, calibrating with 2.2 and D65 should be a starting point. <a href="http://www.luminous-landscape.com/tutorials/why_are_my_prints_too_dark.shtml">Here</a> an excellent tutorial about screen calibration</p>

<p>Here’s the Adobe white paper that explains RGB working spaces:</p>

<p>http://www.adobe.com/digitalimag/pdfs/phscs2ip_colspace.pdf</p>

<p>I think the discussion of the differences is probably a good one, but I have never (well hardly) ever used any of these since color management became sophisticated on computers. While I think it is great to have as many colors as possible remain I am a bit more pragmatic. I want the colors I see to reproduce as I see them. </p>

<p>Maybe because it was industry standard for printing (offset) and I learned color management while producing images for print (magazines, brochures etc), I always use ColorMatchRGB. For me, I have found it just works better and my prints--fine art or offset in a magazine--reproduce the way I want them to. I play with both AdobeRGB and ProPhotoRGB now and then but always come back to liking the way things process and print with ColorMatch (how they translate to the colorspace of the output devices, that is) and have never felt that I gave up anything. In fact, when I am working an image to get it to print, I have more trouble getting the desired result (my desired look) in other color spaces. Bottom line, I don't think it matters what space you use as long as you get the results you intend from your images--just my opinion.</p>

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<p>I want the colors I see to reproduce as I see them.</p>

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<p>Here’s where you need to study the white paper from Adobe! What you can see (on one or more displays) and what you can print (on one or more printers) is vastly different! Which printer, which display? Today’s technology or technology the we may have in 2 years, 5 years? The two differences (what you can see and what you can print) mean you need to compromise the color in one or the other, even today. Data your camera can capture and a printer can reproduce fall outside the gamut of any modern display. Are you willing to throw away colors you can print (and see on the print) you can’t see on the display?</p>

<p>Andrew, I want an image to look like--limited by the medium to be sure--the way I want it to look. Today's better monitors can see all or most of AdobeRGB--some more, including mine. I still don't like the way my images work in AdobeRGB and can get them where I want in ColorMatch whereas they fall short in other spaces.</p>

<p>Many media today also produce colors that exceed AdobeRGB but does it matter if you can't get an image to look as you want it to look in that space? Color spaces also affect how an image is pushed around in your adjustment layers and I prefer the way things are rendered and the results I get in ColorMatch--it is a preference. If in the future there are monitors and output devices--or even new color spaces, I will experiment with those to see if I want to change. I honestly am not concerned with my images today except that they look as I want them to look today. Hopefully, I am more interested in the new work I am producing in the future but can always rescan or re-output and work images in a new space to meet my needs if I see some advantage to doing so. If I am printing a series of work, a limited edition, then it is important that the works remain consistent and my current set up insures that.</p>

<p>My feeling--and my experience--is that my interpretation of an image is more likely to change over time than 2 dimensional output. I have been using Colormatch for almost 15 years now and there have been a lot of changes over that time--mostly in how I interpret images even though monitors and output devices and media are better--my space still gives me what I want--bottom line, that is what is important.</p>

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<p>I still don't like the way my images work in AdobeRGB and can get them where I want in ColorMatch whereas they fall short in other spaces.</p>

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<p>Using the same output profile, there should be no difference other than a lack of colors that clip in a smaller original working space. But I don’t know what you mean by “fall short”. </p>

 

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<p>Many media today also produce colors that exceed AdobeRGB but does it matter if you can't get an image to look as you want it to look in that space? </p>

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<p>Again, this isn’t clear. In terms of look, here you can see a screen capture of an image in Adobe RGB vs ColorMatch RGB from a wide gamut display. They appear identical! That’s supposed to be the case too. The numbers are indeed different, the color appearance isn’t as one would see moving from a larger (ProPhoto RGB) to a much smaller (sRGB) conversion in an ICC aware application. </p>

<p>Outside an ICC aware application, you run into problems. So sRGB (and very close to it, ColorMatch RGB), the color appearance of a larger space would look poor and incorrect. That’s the fault of the application. Here you see that in Photoshop, an ICC aware app, ColorMatch looks just like Adobe RGB (1998) as would be the case with sRGB or ProPhoto RGB. The big difference is what ends up in the output color space! <img src="http://digitaldog.net/files/CMvsARGB.jpg" alt="" width="1830" height="786" /></p>

 

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<p>I have been using Colormatch for almost 15 years now and there have been a lot of changes over that time-</p>

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<p>ColorMatch was designed a very long time ago to describe the output of a Radius PressView with a gamma encoding (1.8) designed for conversion to CMYK. Otherwise its not much different than sRGB (a tiny bit bigger, the main difference is it doesn’t have an sRGB TRC). Its a fine space, but its limited in its gamut size, just like sRGB. If it works for you, great. Its severely limited for those in raw workflows that are printing to anything with a wider gamut than a CMYK press. And if you are using an Adobe raw workflow, you’re using ProPhoto RGB if you know it or not, although you have the option of then throwing away a good deal of color data for some questionable reasons. </p>

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<p>Using the same output profile, there should be no difference other than a lack of colors that clip in a smaller original working space. But I don’t know what you mean by “fall short”.</p>

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<p>Basically, the difference is just that a curve layer or other adjustment layer in one space doesn't always work the same in every color space--the resulting image can be different. Although they generally do disappear when I flatten an image, I have also seen more banding appear in layered files with other profiles as compared to ColorMatch--particularly in blue skies.</p>

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<p>And if you are using an Adobe raw workflow, you’re using ProPhoto RGB if you know it or not, although you have the option of then throwing away a good deal of color data for some questionable reasons.</p>

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<p>It isn't questionable unless you don't know what you are doing or have the experience to know what you are doing is the best course to meeting your needs.</p>

<p>Theory is all well and good but isn't it most important how images work when they are output? If I am not happy with it in a different space then that really is all that matters, isn't it? At least for me.</p>

<p>Theoretically speaking, let's examine someone using say AdobeRGB and a smaller space that fits into their monitor space--say sRGB to use an example in the paper you referenced. One specific example there was that the green can't get as saturated in sRGB as in AdobeRGB, technically you are losing something by the reasoning presented if you are working in sRGB. But you can't see that more saturated green if your monitor doesn't cover the AdobeRGB gamut, can you? So, do you really know what you have in your file? I don't think so. So you decide to send your wider gamut file to an ad agency or you make a print. The output medium is something that captures all of the AdobeRGB gamut and wow, an awful shade of green shows up that you never saw but was there all the time--doesn't feel good to have an agency call and ask what is going on or never call again because you can't process a file. This may not happen in many cases, but only one case can lose a client or cause you to rework a file, blind, to try to get the image where you want it to be.</p>

<p>I have always had just the opposite results (regardless of the fact that I like the space anyway). I have had some of the largest agencies in the country be reluctant at receiving digital files (as late as 2005) because of the messes they got from good photographers. My files always output exactly as my proof prints (printed on wider gamut paper than my files) because I knew what was in my file and the colors that were there were exactly what I wanted them to be because I could see them. I have had calls from Art Directors and Production People thanking me because of this.</p>

<p>We don't let surgeons operate on us blind so why would we want to work on a visual medium blind? Does it really make sense?</p>

<p>So my point, and one that I have felt pretty strongly about for a long time, is that if I can--on a more limited gamut monitor--create an image that looks exactly how I want it to look and in a color space very similar to my monitor then any print I make on a paper with a similar or larger gamut should look like the image I created--except for the difference of not being backlit. If I create an image on a limited gamut monitor as compared to my working color space and print on a color space that encompasses that working color space, there should be some surprises--maybe good or maybe bad--but certainly different.</p>

<p>I have no bone to pick with anyone using other spaces or doing things any other way but brought this point up to suggest that there are alternatives to generally accepted parameters that can, and do, work well.</p>

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<p>Basically, the difference is just that a curve layer or other adjustment layer in one space doesn't always work the same in every color space</p>

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<p>Well they have a different gamma encoding. The RGB values are different. This is totally expected. </p>

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<p> I have also seen more banding appear in layered files with other profiles as compared to ColorMatch--particularly in blue skies.</p>

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<p>You should be working in 16-bit assuming the banding is in the images (not the display which is possible depending on the display and calibration). </p>

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<p>Theory is all well and good but isn't it most important how images work when they are output?</p>

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<p>Yup, that’s why so many of us use a wider gamut working space because we can see the benefits on a device who’s gamut is wider than our displays and in this example ColorMatch RGB. The image I showed above is an example. The biggest area where Adobe RGB exceeds sRGB/ColorMatch RGB is green. Output that image in sRGB vs. Adobe RGB to a decent ink jet that exceeds both, you’ll see a more saturated green that the printer can produce. Now maybe that isn’t important to you. In the example above, the entire point of the image, the theme is about the green. <br>

Its all about maximizing the data you have and the data you can reproduce. For many of us, that’s very critical. Being safe, using a lower gamut working space is fine, but that’s not a story about maximizing the image quality for those of us that create images. Working solely in an sRGB (or ColorMatch RGB) workflow is safe, it will produce very good results. It doesn’t produce the best possible results. If someone’s goal is to use the tools and technology to their highest degree, a wider gamut space, something the capture device and output devices support is necessary. </p>

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<p>One specific example there was that the green can't get as saturated in sRGB as in AdobeRGB, technically you are losing something by the reasoning presented if you are working in sRGB. But you can't see that more saturated green if your monitor doesn't cover the AdobeRGB gamut?</p>

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<p>But you CAN on the output device! If all you care about is the display, stick with sRGB. Again, you have the option: use a working space (which is an archive space too, after what could be hours editing an image) that is fully visible on your display but short for output needs OR use all the colors you captured and can output to any device today and in the future, but not see colors outside the display gamut? Most would rather have the data and use it for the final print process. </p>

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<p>So, do you really know what you have in your file? </p>

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<p>You do when you print it. Today and in the future to any number of printers. Just because data falls outside your current display gamut doesn’t mean its usable data. It is. </p>

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<p>an awful shade of green shows up that you never saw but was there all the time</p>

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<p>Its only awful if you make it that way, but doing something silly like moving the Hue/Sat slider when you don’t see anything updating on your display. That’s when you back off because you <em>could</em> be altering colors you can’t see on that single, low gamut device. </p>

<p>Andrew, you seem a bit condescending here. I know your background and a simple search of mine here would indicate that I do know what I am doing--as I am sure you do. As I said, I have no bone to pick and I know what you are saying is right--for you but it hasn't worked well for me--it is just different strokes my friend.</p>

<p>The banding is in 16 bit, which is how I work. My prints are optimal as they are exactly how I want them, thank you.</p>

<p>Yes, great results are made using wider gamut spaces and printing proofs and correcting once one sees what is actually in the file (or how something prints) is no different than what anyone should do regardless of their color space. But when I send a file off, I don't want surprises for my clients and I don't get them.</p>

<p>My points are not solely directed to you but to anyone who might want to understand why working in a space far greater in gamut than ColorMatch is useful (and what ColorMatch was initially designed for). </p>

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<p>The banding is in 16 bit, which is how I work. </p>

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<p>You are saying you have 16-bit files that exhibit banding? I’d love to see that (it be a first). Unless they started life as 8-bit per color and then were converted to 16-bit (that doesn’t work, isn’t useful). </p>

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<p>But when I send a file off, I don't want surprises for my clients and I don't get them.</p>

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<p>No one does, hence the reason for modern color management. That doesn’t preclude wide gamut spaces. </p>

<p>I shoot RAW and when I give the JPG files to clients, I always save them in sRGB JPG. I figure since monitor can only display sRGB and commercial printers (Walmart, Costco etc.) expect sRGB, it is better to give them sRGB JPG than Adobe RGB JPG.</p>

<p>Could anyone comment on this (giving clients sRGB JPGs)? Thanks.</p>

<p> </p>

<p>Green Photog, since you are mentioning Walmart and Costco, I am assuming your clients might be retail clients--portraits and weddings and such? If that is that case, I think delivering sRGB files is pretty much the standard just for the reason you mention. Most retail clients wont have the software or the know how to change the color space or know what to change the color space to and most consumer cameras are set to shoot sRGB by default for this reason.</p>

<p>Safest color space to hand to clients who don’t understand color management is sRGB. But you can process all the data and edits in ProPhoto, 16-bit, then save off an iteration in sRGB 8bit JPEG for such needs without throwing the baby out with the bath water. </p>

 

<p>Hi John and Andrew, thank you for your response. I keep my RAW files mainly for my own benefits as once the clients got their files, they probably will never contact me again.</p>

 

 

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<p>Safest color space to hand to clients who don’t understand color management is sRGB. But you can process all the data and edits in ProPhoto, 16-bit, then save off an iteration in sRGB 8bit JPEG for such needs without throwing the baby out with the bath water.</p>

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<p>Should one "convert" to a new color space, or "assign"? Is it different in Photoshop than it is in Nikon NX2?</p>

 

 

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<p>Should one "convert" to a new color space, or "assign"? Is it different in Photoshop than it is in Nikon NX2?</p>

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Convert. You NEVER assign unless the data is in the color space that isn’t tagged (embedded) with a profile or (a very rare case), embedded with the wrong profile (something those who don’t understand what Assign profile does and uses this command incorrectly). <br>

<em>Assign</em>: Don’t change the RGB values, change the meaning (definition) or scale of the numbers. <br>

<em>Convert</em>: Change the numbers from one color space to another color space. </p>

<p>Big, big difference! </p>

<p>Thanks Andrew--that helped, and allowed me make more sense of Nikon's limited, and therefore cryptic, explanation. Some may find this page especially helpful: http://www.colormanagementinfo.com/page1/page10/page10.html</p>