Color Test

[Ldina]

This is a Color Test (for my own illumination) and I'm sure others will have some wisdom to share.

In the past, the safe route was to work in a wider gamut color space to preserve color and avoid premature clipping (ProPhoto RGB, Adobe RGB, P3, etc), then convert my small JPG files to sRGB for emailing and web posts to be sure other saw essentially what I saw (limited to sRGB, of course). That was a good approach for images heading to an inkjet or to a press too because sRGB whacked a lot of colors that can be printed using CMYK inks (not to mention additional ink colors and spot colors). I have a good friend who is an experienced, color management professional and it's his opinion that converting to sRGB is no longer necessary (with a few limited exceptions here and there). Most browsers and email clients are color managed these days. I respect his judgement, but it's always nice to test and get some confirmation and feedback, which is what this post is all about.

I created a composite image in AP v2.4.0 and used Apple's Display-P3 profile in this file. I purposely chose an image that has skin tones, some subtle shades, some bright colorful portions, then added some grayscale and fully saturated color patches for evaluation. I wanted any differences to be visible if they existed. ( I haven't viewed the results on this forum yet, as I am still creating the original post.) I'll attach the original AP file, along with 3 different exported JPG versions, all 2000px on the long side, at 85% JPG quality.

1. First, I exported the Display P3 original from AP and embedded the Display P3 profile in my first export. On my Retina display, that is the brightest JPG of the three, since my display IS a P3 display. So, the color patches retain their original saturation and brightness.

2. Next, I exported the Display P3 file from AP, but on export, I converted the file to sRGB 1966 and embedded that profile in the export. As expected, the saturated color patches are less saturated because they are now clipped to the smaller sRGB gamut. The rest of the image looks pretty much identical on my Retina display and also on an old Viewsonic sRGB gamut LCD display (about 15 years old). That is what I was expecting and hoping for. 

3. The third JPG image export I did differently. First, I converted my original AP file from Display P3 to sRGB. Then, I exported to sRGB. The color patches look the same as in No. 2 above, which I expected. My daughter also looks the same overall. However, I was a bit surprised to see that the foliage in the background showed a tonal shift (slightly darker) compared the the sRGB exported from a Display P3 working space. This was the same result on my Retina and Viewsonic monitors. As mentioned, I haven't seen the result as posted on the forum yet, but I will after clicking the "Submit" button.

By the way, I chose Apple's "Display-P3" profile for this test. Why? It uses a tone curve that looks identical (or at least very similar) to the tone curve in sRGB. This should minimize any tonal changes between sRGB and Display P3 (which is why I was a bit surprised to see the foliage in No.3 above different from No. 2 above). DCI-P3 (at least the version I have) is an ICC v2 profile and was supposedly designed with cinemas and theaters in mind, so they use a very low white luminance and a gamma of 2.6. For the work I do, I felt Display P3 made more sense. BTW, the Apple Display-P3 profile I have is an ICC v4 profile. 

So, there it is. I suspect some people will have some interesting feedback, so bring it on!! I'm about to click Submit, so I'll get a look at the post at the same time you do. 

Thanks.

P3-sRGB Test.afphoto

[Ldina]

OK, just saw my posted results. The Display-P3 JPG I uploaded to the forum looks desaturated compared to the other two, which suggests to me that images posted on this forum "assume" the file is sRGB (even though it has an embedded Display P3 profile. 

[Ldina]

BTW, if interested, here is a link to download Display P3 from the ICC website, with a lot of information about its parameters. 

https://www.color.org/chardata/rgb/DisplayP3.xalter

[thomaso]

1 hour ago, Ldina said:

The Display-P3 JPG I uploaded to the forum looks desaturated compared to the other two, which suggests to me that images posted on this forum "assume" the file is sRGB (even though it has an embedded Display P3 profile. 

The forum's software strips the colour profile from an uploaded JPG (and may recompress it with ~85%). You can also compare the result when you re-download your uploaded images and view them in a colour-managed app. To upload images with profiles you need to ZIP them. If you just want to view your image in your brwoser you can drag it to an open browser window.

In addition to the colour management skills of a browser software, the viewer's monitor hardware must also support the colours supplied in order to display them correctly and without loss. To avoid any colour shift it may also need to be calibrated. Therefore, you don't have full control over how your images occur on different users' monitors.

If you want to check your individual setup you could use the various available websites, for instance…

https://webkit.org/blog-files/color-gamut/

https://chromachecker.com/webbrowser/en/manual

https://cameratico.com/tools/web-browser-color-management-test/

https://www.color.org/profileview2.xalter

P.S.: for large images it may be useful to resize them in the forum's window when creating a post. If you double-click an image placed in your text you can set a wanted size. This way you can achieve that 3 images may get compared without the need to scroll. If forum readers want to see those in their full size they can double-click to enlarge them.

[walt.farrell]

1 hour ago, Ldina said:

OK, just saw my posted results. The Display-P3 JPG I uploaded to the forum looks desaturated compared to the other two, which suggests to me that images posted on this forum "assume" the file is sRGB (even though it has an embedded Display P3 profile. 

The forum provides 2 forms of each image; one for viewing inline, and another if you click on the inline image that will show it in separate out-of-line "window".

At a minimum I would make any comparisons using the out-of-line version (or after you have that version, you might right-click on it and tell your browser to display it in a new tab).

I do not know if these two versions are handled differently for color management, but you also have the possibility of uploading zip files instead (or also), as thomaso mentioned.

[Ldina]

@thomaso Thanks, Thomaso. 

I've been a color management geek since about 2000. All my devices are calibrated...monitors, printers, papers, ambient lighting, viewing lights, etc. I agree that what the end viewer sees is not fully under our control, due to different monitors, gamuts, monitor settings, calibration, ambient lighting, etc. I'd rather dispense with the extra step of converting my images to sRGB entirely so people viewing a wide gamut document (that preserves more color information) will see what they'd see in an sRGB image if viewed on an sRGB capable display. If the user has a wider gamut display, they'll see the image in its original, full color state. That's the way the world is moving, and that seems to work fine IF color management is enabled and profiles are honored. 

I'd have expected Serif, which creates "high-end" photo editing software, would have a color-managed forum, so uploaded images are presented as accurately as possible, as long as the profile is embedded. The user's setup is beyond our control.

At least I know they strip the profile and just assume sRGB. Rather pitiful. I'd say it's time they upgraded their forum software. 

 

Edited to add this comment...

By the way, thanks for the tip about resizing images when creating the original post. I didn't know about that, but will be very useful in the future!

[Ldina]

@walt.farrell Thanks, Walt.

Zipped files are fine if people want to download a copy to their computer to play around with it. For routine image viewing on a forum, they should be color managed by default. Either method you mentioned displays the JPG with the embedded P3 profile washed out and desaturated. So, apparently, the forum software is just assuming sRGB and ignoring the profile. I'd expect this from some unsophisticated websites, but not from a company that makes photo editing software, at least at this point in time. But, there it is, so I guess I'll have to work around it until (or if) they change it.

sRGB is an ancient paradigm, created in the 1990s, when monitors were very limited and some reasonable standard was necessary. It's time we left sRGB behind and moved on. At least I think so.

edited....I previously had written "1960s", which was a typo on my part. Sorry about that. 

[thomaso]

33 minutes ago, walt.farrell said:

The forum provides 2 forms of each image; one for viewing inline, (…) I would make any comparisons using the out-of-line version

Do you mean the "2 forms of each image" are based on 2 different image/file versions? To me its seem to be just 2 viewing modes with the "out-of-line version" as a kind of "gallery view" with its two back/fwd arrow buttons.

[Old Bruce]

48 minutes ago, Ldina said:

sRGB is an ancient paradigm, created in the 1960s,

1996 actually. 

[Ldina]

4 minutes ago, Old Bruce said:

1996 actually. 

oops...typo! 🥴 

[thomaso]

1 hour ago, Ldina said:

I'd have expected Serif, which creates "high-end" photo editing software, would have a color-managed forum, so uploaded images are presented as accurately as possible, as long as the profile is embedded.

I assume there is a large majority of topics in the Affinity forums that are not related to colour profiles embedded in image files. And even if, there seem to be more issues discussed resulting in wrong user settings … or issues with RAW / HDR / 32-bit and not directly related to embedded colour profiles that could get viewed correctly as online resource any browser app.

FWIW, recently in the forum of the developer of this forum software:
https://invisioncommunity.com/forums/topic/477542-image-saturation-on-jpg-uploaded-to-forum/

Colour management is just one (a secondary, minor?) aspect for both the developers of a forums software and also for their clients (e.g. Serif), for instance:
https://invisioncommunity.com/forums/topic/477126-image-compression/

[Ldina]

6 minutes ago, thomaso said:

FWIW, recently in the forum of the developer of this forum software:

@thomaso Thanks again. Agreed, there are plenty of other important subjects being discussed. 

It's 2024 and color management is now mainstream in nearly all browsers and email clients, most photo websites, etc. It's time Invision caught up with the times and built color management into their forum management software. We're talking "basic fundamentals" here. 

I'll probably use Display P3 as my default profile from now on, even when sharing JPGs and PNGs via email and the internet. That will work for most viewers. I'll just have to live with posting washed out images on this forum. If I have any color-critical images to post, I guess I'll just have to dumb them down to sRGB. 

 

[Old Bruce]

8 minutes ago, Ldina said:

If I have any color-critical images to post, I guess I'll just have to dumb them down to sRGB. 

Or zip them and let those who are interested download and view on their own (differently calibrated) monitors.

[Ldina]

2 minutes ago, Old Bruce said:

Or zip them and let those who are interested download and view on their own (differently calibrated) monitors.

Thanks...true enough. Guess we have to live with the limitations of the forum software. 🙁