Soft Proof with 3D LUTs for Photoshop

[shijan]

<p>Let me tell you, i always got a little problem with correcting of wide gamut images in Photoshop. Calibrated your display or not there is no way to see them exactly as they appears after converting to sRGB when looking on them through monitor profile (View-Proof Setup-Monitor RGB). There is always some shifts in color and the more display profile gamma different of sRGB gamma, the greater the shifts.<br>

If look further here is a real life example how things happens when we export image to sRGB and lwatch in on regular display:<br>

<strong>Image with ProPhoto RGB profile -> Converted sRGB -> Correction with monitor profile</strong><br>

Here is how we look on regular sRGB images in photoshop or any other image viewer:<br /><strong>image with sRGB profile -> correction with monitor profile</strong><br>

Here what we got if the picture is in wide color space:<br /><strong>Image with ProPhoto RGB profile -> Convert directly to monitor profile (Proof Setup option can't be used here)</strong><br>

It may looks like correct but not for real life with small gamut displays. In this way photoshop bypasses one step in its color management. So what can we do? We can use 3D LUTS! It so happens that one time in After Effects plugins Color Profile Converter and Lut Buddy met each other, and its became clear that it is possible to create 3D LUT for realtime conversion to sRGB. to use it just create Adjustment Layer Color Lookup and put on top of all.<br>

And here how the situation looks now:<br /><strong>Image with ProPhoto RGB profile -> Realtime converted sRGB with LUT -> Correction with monitor profile (Proof Setup-Monitor RGB enabled)</strong><br>

Here is a soft proof luts pack for some basic color spaces: <strong><a href="http://cl.ly/Ro0U">http://cl.ly/Ro0U</a></strong><br>

And don't forget to disable this proof layer when export final image!<br>

BTW. For those who would like to create same luts here is some screenshots with settings in After Effects. For max accuracy create 32 bit project with same color space FROM which you woulld like to convert. there is also a tons of lessons about how to use Lut Buddy, its very easy<br>

<a href="http://forum.rudtp.ru/attachments/3323063-jpg.59601/"><img src="http://forum.rudtp.ru/attachments/3323063-jpg.59601/" alt="" /></a>.<img src="http://forum.rudtp.ru/attachments/3323064-jpg.59602/" alt="" /></p>

<p> <a href="http://forum.rudtp.ru/attachments/3323063-jpg.59601/"><img src="http://forum.rudtp.ru/attachments/3323065-jpg.59603/" alt="" /></a></p>

<p> </p>

[digitaldog]

<blockquote>

<p> Calibrated your display or not there is no way to see them exactly as they appears after converting to sRGB when looking on them through monitor profile (View-Proof Setup-Monitor RGB).</p>

</blockquote>

<p>On the same display? Never seen that. The <em>Proof, Setup-Monitor RGB</em> is to show you how the image would look on that system in a non ICC aware application. I'm not even sure why that's important, viewing any color space in a non ICC aware application is viewing it incorrectly. </p>

[shijan]

<p>Andrew, let me explain my observations regarding this problem, but its not a short story and as so as i still need to understand many things it is possible that my findings are incorrect too.<br />Long time ago i got a nice Samsung 959 NF CRT display, later it became too dim and i switched to e-ips Dell u2311h. first thing that i notice is wtf, where is all my lovely shadows? I try to watch some pictures and movies and all those looking like with shadow recovery filter (in movies sometimes i even clearly can saw the vfx compositing seams and blended layers in shadows). So i decide to purchase i1 LT calibration device and build custom profile to correct all those madness. I try few calibration apps and ended up with dispcalGUI because in addition to gamma settings it able to make a little dimple in shadows to mimic CRT look. First times i do calibrations with gamma setting 2.2 as so as it was generaly accepted, but later find that display gamma can vary depending of view conditions and personal preferences (for example i find some recommendations for ITU-R BT.709 and other broadcast video formats regarding use display with 2.35 gamma. So i try to experimenting with gamma settings and ended up with 2.37 value. and only after that all images and videos became look as they should be look in my opinion (i used Movist for movies and Xee for viewing images), but in Photoshop without enabling (edit-proof setup-monitor rgb) i still got those washed look.<br>

Today after your reply i made one more test and find that modern web browsers behave same as Photoshop - if i put into them image with embed sRGB profile i see washed shadows, and if i don't assign any profile to same image i see it as i expect with nice deep and smooth shadows.<br>

In addition to photos and movies i test 16 bit images with generated black and white rgadients, and here is the result - if id disable (proof setup-monitor rgb) in photoshop or look at the image with assigned profile in web browser the gradient looks terrible with banding and very non uniform shade from black to white. But if i look on the same gradient with enabled (proof setup-monitor rgb) in photoshop or if i put image without color profile in web browser it became look smooth and eye candy (Unfortunately it is impossible to show this difference with screenshots). So it means that Xee is not a color management application and Movist look like too.<br>

But now i got more questions than before. Is it all means that monitor profile don't affects the look of the images in color managed apps? If so what the sense of monitor calibration at all? Maybe there is a sense to build and assign custom icc profile with gamma close to classic 2.2 than to dumb sRGB curve and so that people can see my works same as i expect in their color managed browsers?<br>

And finally. As i wrote before - in past CRT displays got gamma 2.4, broadcast video formats recommend gamma 2.37 for displays, sometimes even gamma 2.5, and so on… i believe that sRGB, REC and other old broadcast image and video profiles were developed to be compensated by very strong additional monitor gamma correction. But nowadays it appears that color managed applications and LCD displays able to produce native sRGB gamma kill all this concepts.<br />Thats how my theory looks like, please correct me if i wrong.</p>

[digitaldog]

<p>There are two conditions going on here: one where you are working in an ICC or color managed environment or application and one when you are not. <br>

In color managed app's, the display TRC gamma doesn't mater really. The ICC profile and the color management software use a Display Using Monitor Compensation architecture. Outside ICC aware applications, the app simply sends the numbers to the display. You might have calibrated the display, but the profile which understands that behavior and the numbers in the document (in sRGB or any other color space) is simply not understood. When you used Photoshop's view>Display RGB, you are treating this ICC aware application like a non color managed app (Show me what my images would look like outside Photoshop or all ICC aware applications on <strong>this</strong> system alone). In the ICC mode, it doesn't matter what the gamma of the display or the working space is. That's all accounted for. That color appearance is correct at least in terms of the calibration you've produced. You can of course calibrate to some behavior that will make the images look wrong but that's not something you want to do. </p>

<blockquote>

<p>in Photoshop without enabling (edit-proof setup-monitor rgb) i still got those washed look.</p>

</blockquote>

<p>Photoshop is showing you how 'wrong' the color appears without color management on that system with that proof on. If the color isn't correct otherwise, it is your display calibration targets (settings). <br>

Test what should be considered correct color by examining a reference image in Photoshop. Ther is one here: http://digitaldog.net/files/Printer%20Test%20file.jpg</p>

[warren_hatch]

Dimity,

 

In you latest post you mention 'assigning' profiles at least twice in order to get your images to sRGB. Andrew is the ultimate authority on

these matters, but I suggest using Photoshop's 'Edit/Convert to Profile' command to accomplish your change from one color space to

another. Perhaps I read your post too literally, if so I apologize for wasting you time.

 

Kind regards,

 

Warren

[shijan]

<p>Just made new profile for test with L* curve, testing it now... <br /> So thanks to CMS i can view Wide gamut images which have build in profile with web browser on small gamut display - i'm very impressed. But back to real life - <strong>99,9% of the web consists of images which are actually sRGB but without an embedded profile, and thanks to CMS i see them differently than same sRGB images but with embed profiles. And also the image look correct from the <strong>CMS view appears to be incorrect from human point of view. </strong>Where is the logic in this system? </strong><br /> Warren, i suppose 'assigning' srgb profile to image that was created in srgb but saved without profile, read please the overall text...</p>

[shijan]

<p>Here are some test results:<br />OSX 10.6.8, Photoshop, grayscale gradient generated in 16 bit image created with sRGB working color space. Photoshop restarted every time after changing the profile in OSX settings. Tested standard gamut display.<br /><em>Terms:</em><br /><em><strong>Unproofed</strong> - defalut, with disabled (View-Proof Setup-Monitor RGB)</em><br /><em><strong>Proofed</strong> - with enabled (View-Proof Setup-Monitor RGB)</em><br>

<em> </em><br>

<strong>System profile done with sRGB gamma</strong><br>

Unproofed - subjectively not very natural look, non smooth gradient in the shadows<br />Proofed - exactly same look<br>

<strong>system profile done with Gamma 2.37</strong><br />Unproofed - subjectively worst look, poor shadows with very visible non uniform gaps.<br />Proofed - subjectively nice smooth gradient, nice deep cinematic shadows as it was expected<br>

<strong>system profile done with L* gamma</strong><br />Unproofed - subjectively very smooth uniform gradient but too low contrast and weak shadows.<br />Proofed - subjectively nice organic look, maybe even too clinically uniform, more-less good shadows, overall looks like unproofed look with gamma 2.37 profile<br>

exactly same results i get in web browser tests when i put into them same image with and without assigned profile.<br>

now the bad thing about L* gamma when i try to made additional adjustment in dispcalGUI to compensate the lack of deep black colors on LCD it behaves in opposite way - it recovers blacks.<br>

don't know why, but in cmm enabled apps the display gamma setting affects all things in some kind of flipped way, maybe because cmm engines designed around something like L* gamma…<br>

The separate story is OSX QuickLook app - if i put there image without assigned profile it handle it same as Xee and web browser, but when i open same image with assigned sRGB profile it shows me it in very unique way with its own crazy shifted gamma (not same as photoshop shows)<br>

Now lets test same image in non cmm enabled application - with or without assigned profile the image look the same and its gamma adequately depends of display profile gamma. it's simple. The downside - i cant watch wide gamut images on non wide gamut display. But solution exists - see my first post.<br>

<strong>so… my thought - global color management in its current stage its madness without any common structure. And without global common crossplatform and crossapplication structure it is looses its sense and main aim, and became not a color manager but color variator.</strong></p>

[shijan]

<p>additional info - system profile with Gamma 2.37 done in dispcalGUI with Black Output Offset set to 98% so the curve looks like this:</p><div></div>

[digitaldog]

<blockquote>

<p>But back to real life - <strong>99,9% of the web consists of images which are actually sRGB but without an embedded profile, and thanks to CMS i see them differently than same sRGB images but with embed profiles.</strong></p>

</blockquote>

<p><strong> </strong><br>

Correct and there is nothing you can do about this. You must work in ICC aware applications with or without sRGB to see that data correctly. Doesn't matter if sRGB is used, that doesn't guarantee proper color appearance outside non ICC aware applications. Non ICC aware applications don't even know what sRGB is let alone the display profile. <br>

You do not need to concern yourself with gamma. In ICC aware application, it doesn't matter, this is all known and accounted for. Outside of non ICC aware applications, the previews are not correct unless you are lucky. So in this case, still no reason to concern yourself with gamma. </p>

[shijan]

<p>its sad but reading forums here seems this problem presents from the beginning of time and its really strange why for few dozens of years the OS and software developers can't find a global consensus for color handling.<br /> here is also some thoughts about colors:<br /> all tests done on sRGB images.<br /> if i set system profile to sRGB or to generated monitor profile (which use same sRGB primaries) all colors , tagged and untagged everywhere with any settings looks the same (except quicklook, but lets don't touch this part of strange software:). This is good but on my display overall colors look feels a little wrong, grayscale UI elements became a little blue and so on. So the solution seems simple as hell - JUST TAG IN REALTIME ALL UNTAGGED IMAGES ON SYSTEM LEVEL TO sRGB, AND CORRECT THEM WITH DISPLAY PROFILE (as overlay LUT). What else should usual people expect of global color managemet and display calibration? I don't talk about editing apps now, i lust talk about web browsers and simple image viewers. Why companies do things so complicated, i don't know...<br /> Now lets see what colors my Dell display can actually reproduce. here is plot before and after calibration. This image explains why i see a little warmer colors when i turn on <em>(View-Proof Setup-Monitor RGB)</em></p><div></div>

[shijan]

<p>btw. same concept can be done for for wide gamut displays support on system level: any untagged sRGB or sRGB -> upscale to AdobeRGB and correct with Display profile. </p>

[digitaldog]

<blockquote>

<p>its sad but reading forums here seems this problem presents from the beginning of time and its really strange why for few dozens of years the OS and software developers can't find a global consensus for color handling.</p>

</blockquote>

<p>Such systems exist and run properly in many products, but not all. IF color is important to you, you need to work in ICC aware applications. </p>

[shijan]

<p>Yep, but various systems and apps have various ideas what color management should be and how it should work. One decide to convert image profile to display profile and anothers choose to convert to sRGB (or even worse to some custom special profile) and then show through display profile (aka old school way) take a look here http://www.gballard.net/firefox/<br>

Another problem seems was in my outdated OS (but sorry i won't switch to Lion anyway) Apple changed Lion 10.7 ColorSync behavior to default untagged and unmanaged color to sRGB (OSX, 10.7 and higher, no longer applies its monitor profile to untagged color or unmanaged color) — this is great news... http://www.gballard.net/photoshop/osx_22_gamma.html<br>

Another thought - various types of displays have various hardware technology which produce different tonality representation (CRT have (had) deep blacks but works not too well in bright light conditions, LCDs opposite have poor blacks if you watch it in the dark room but in decent light conditions looks better than CRT. Maybe OLED displays should solve both problems but i don't get luck to see this displays in reality yet and they are still very far of mass production) so perfect world the global color management should do correction regarding display type too. And all time i tried to do this correction by myself with display profile gamma adjustment based on personal visual appearance, but with enabled color management i can't do this correction anymore. </p>

 

[shijan]

<p>here is nice investigation too <a href="http://www.gballard.net/psd/cmstheory.html">http://www.gballard.net/psd/cmstheory.html</a><br /> chapter Source> sRGB Beware of Windows "half" color management.<br /> in conclusion -<strong> it's extremely important to find some kind of ISO standard or global color management guide lines which EVERYONE will follow</strong>. Are the big companies know about what the hell they done? Maybe we should write a global petition to them?</p>

[digitaldog]

<blockquote>

<p>Yep, but various systems and apps have various ideas what color management should be and how it should work.</p>

</blockquote>

<p>Not really, not in ICC aware app's. About the only major differences in them is how or what they assume for untagged data. In Photoshop the assumption is whatever working space you setup in Color Settings. In Lightroom it is sRGB. On the Mac it's the display profile (which is dumb). On most browsers, it's sRGB. After that, they take the assumption, look at the display profile and produce a preview. Untagged data is unacceptable period. If you tag the data, all the app's will work properly assuming you have a good profile to define the display. </p>

[shijan]

<p>ok Andrew, i'll avoid untagged data for futureproof, even its sRGB. and so the title of this topic should be renamed to something like the "Alternate Soft Proof with 3D LUTs for Photoshop aka how to see how the untagged sRGB will look on your computer, till you work in wide gamut color space" :)</p>

[digitaldog]

<blockquote>

<p>i'll avoid untagged data for futureproof, even its sRGB.</p>

</blockquote>

<p>You have to as ICC aware app's assume something and non ICC aware app's don't know what sRGB or the display profile is. </p>

<blockquote>

<p>aka how to see how the untagged sRGB will look on your computer</p>

</blockquote>

<p>If you have Photoshop, just use the Assign RGB command. Select what profile you wish the numbers to be assumed to be. The preview will update based on that assignment. In the case of untagged sRGB on your display, you'd simply select your display profile. Of in soft proof, "<em>Monitor RGB"</em>. </p>