Issue with sRGB export profiles in Affinity Photo

[rvst]

I use ProPhoto RGB as my working space. When I export to a JPG using the sRGB IEC61966-2.1 profile (and of course I embed the profile), I end up with a substantially different looking photo to the original, almost as if it has subsequently had a non-linear S-shaped curve applied to it. The difference is marked.

I've taken to exporting the file into TIFF format using a ProPhoto RGB profile, importing it into Adobe Lightroom and then exporting that to sRGB, which is a bit of a convoluted workflow. This way, the resulting sRGB JPG looks exactly like what I have on the screen when I have the ProPhoto RGB file loaded in Photo.

Curiously, if I choose to export it with a *wsRGB profile, then I get the expected result - the JPG looks identical to the original file. But of course I don't want to do this, since it's not a properly standardized ICC file.

Anyone have any idea what's going on here?

[v_kyr]

ProPhoto RGB has a much wider gammut (color space) than sRGB, thus ProPhoto RGB offers much more colors which sRGB doesn't.

Thus things may look quite different for the initial ProPhoto high gammut image when converted and saved as a lower gammut image (sRGB) in this case.

 

AFAI recall, the *wsRGB gammuts are defined like the scRGB color gammut. - Aka ...

Quote

scRGB is a wide color gamut RGB color space created by Microsoft and HP that uses the same color primaries and white/black points as the sRGB color space but allows coordinates below zero and greater than one. The full range is −0.5 through just less than +7.5.

Negative numbers enables scRGB to encompass most of the CIE 1931 color space while maintaining simplicity and backward compatibility with sRGB without the complexity of color management. The cost of maintaining compatibility with sRGB is that approximately 80% of the scRGB color space consists of imaginary colors.

Large positive numbers allow high dynamic range images to be represented, though the range is inferior to that of some other high dynamic range formats such as OpenEXR.^[2]

LR/PS etc. do have their own by Adobe created color management engine, which of course long time plays in another league here, than what Affinity uses and is based on (LittleCMS). - And yes, e-sRGB, wsRGB, scRGB are obsolete and not Icc-specified profiles at all, so I too wouldn't use these!

See also:

• What is wsRGB and wscRGB colour profiles?

[rvst]

Forgive me, I don't mean to be snarky in my reply. I know how these different colour spaces work - it's the very reason I use ProPhoto RGB, since it is wide gamut and so are my monitors. I get better colour precision and gradation by working in a wide gamut colour space.

When using a properly colour managed viewer, a ProPhoto RGB and sRGB version of the same photo containing embedded ICC profiles look identical on my monitor, as well they should. 

The only time an sRGB and ProPhoto RGB version of the same file don't look the same is if the ProPhoto RGB file fails to contain an embedded ICC profile or one uses a viewer that is not colour managed, in which case the colours in the ProPhoto RGB version will look all washed out. 

The problem I am referring to is quite different. With Affinity Photo (and ONLY with Affinity Photo), when I export a file to the sRGB colour space using the default sRGB IEC61966-2.1 profile, the file undergoes a transformation of some type. It seems to apply what looks like a non-linear tone curve to the output file. 

I can take the IDENTICAL TIFF file, load it into multiple different pieces of software (Lightroom, On1 are two examples of other software I use) and export it to a sRGB JPG and in every case except for Affinity Photo, it looks identical to the ProPhoto RGB version. 

To investigate this issue further, I just download the ICC v4 and V2 profiles from here: https://www.color.org/srgbprofiles.xalter, imported them both into Affinity Photo and then used these two profiles as the target sRGB profiles for my JPG export. The resulting exported SRGB JPG is correct, matching the ProPhoto version and quite different from the version using the default sRGB IEC61966-2.1 profile.

There appears to be something wrong with the sRGB ICC profile in Affinity (I'm assuming this ICC profile is shipped with Affinity, but I may be wrong).

[v_kyr]

10 hours ago, rvst said:

The problem I am referring to is quite different. With Affinity Photo (and ONLY with Affinity Photo), when I export a file to the sRGB colour space using the default sRGB IEC61966-2.1 profile, the file undergoes a transformation of some type. It seems to apply what looks like a non-linear tone curve to the output file. 

I can take the IDENTICAL TIFF file, load it into multiple different pieces of software (Lightroom, On1 are two examples of other software I use) and export it to a sRGB JPG and in every case except for Affinity Photo, it looks identical to the ProPhoto RGB version.

How do the results look with other color-managed software (LR/PS etc.) when you use there the by your operating system or Affinity supplied sRGB IEC61966-2.1 profile? - If things look Ok there for JPGs and TIFFs then, it's probably an Affinity profile handing related problem.

10 hours ago, rvst said:

To investigate this issue further, I just download the ICC v4 and V2 profiles from here: https://www.color.org/srgbprofiles.xalter, imported them both into Affinity Photo and then used these two profiles as the target sRGB profiles for my JPG export. The resulting exported SRGB JPG is correct, matching the ProPhoto version and quite different from the version using the default sRGB IEC61966-2.1 profile.

Those are much newer over time reworked sRGB profile versions, which might behave nowadays overall better in the meantime like that older sRGB IEC61966-2.1 profile version.

10 hours ago, rvst said:

There appears to be something wrong with the sRGB ICC profile in Affinity (I'm assuming this ICC profile is shipped with Affinity, but I may be wrong).

Maybe, it might depend on the profile and it's origin, or the way Affinity is handling this one internally then.

Though if I look onto the old Mac I'am actually sitting on, I can find just the following profiles inside of Affinity Photo ...

 

And the old MacOS El Capitan system here has the "sRGB IEC61966-2.1" profile installed under it's system color resources.

 

I also recall that in the past there were quite some differences and changes between certain sRGB profiles ...

sRGB: Primary valences:

R 0.6400/0.3300
G 0.3000/0.6000
B 0.1500/0.0600
Gamma: 2.2

sRGB IEC 61966-21: Primary valences:

R 0.6485/0.3309
G 0.3212/0.5978
B 0.1559/0.0660
Gamma: LUT, not quite 2.2 accordingly, since darker values are raised (due to internal if then condition)

... but it might be that Affinity's internal color-management engine handles and works slightly different with the values defined inside the sRGB IEC 61966-21 profile. - Further you might test/check if it only is effected by using TIFF files, or if it is of general nature here (...when using JPG/PNG etc. too).

 

[R C-R]

7 hours ago, v_kyr said:

And the old MacOS El Capitan system here has the "sRGB IEC61966-2.1" profile installed under it's system color resources.

My iMac running Catalina has the same profile at the same size & same creation date in the same system location. It also has another smaller (596 bytes) & newer (creation date 3/10/17) one of the same name in ~/Library/Application Support/GraphicsConverter/Profiles, presumably used only by GraphicsConverter.app, but I am not sure about that.

In AP I find the following 15 profiles at path /Applications/Affinity Photo.app/Contents/Resources:

• AdobeRGB1998.icc
• AppleRGB.icc
• CoatedFOGRA27.icc
• CoatedFOGRA39.icc
• ColorMatchRGB.icc
• JapanColor2001Coated.icc
• JapanColor2001Uncoated.icc
• JapanColor2002Newspaper.icc
• JapanWebCoated.icc
• UncoatedFOGRA29.icc
• USSheetfedCoated.icc
• USSheetfedUncoated.icc
• USWebCoatedSWOP.icc
• USWebUncoated.icc
• WebCoatedFOGRA28.icc

The same 15 are in the Resources folders of AD & APub. As you can see, there is no sRGB profile in any of them.

As an aside, I downloaded the sRGB_v4_ICC_preference.icc from https://www.color.org/srgbprofiles.xalter & installed it in AP. I noticed that both in AP & in the ColorSync Utility it's description (the 'desc' tag in ColorSync Utility) is sRGB_v4_ICC_preference perceptual intent beta. I'm not sure what to make of the "beta" in that tag.

I did the same for the sRGB_ICC_v4_Appearance.icc file at https://www.color.org/profiles/srgb_appearance.xalter. That is the newest (creation date 6/8/16) of the sRGB v4 profiles I can find. I have not yet tried using any of them -- I am not even sure what I should be looking for.

[rvst]

I think I have tracked down the problem.

It's an issue of ICC v2 versus v4 profiles.

All of the professional graphics software I have displays these JPGs that use the sRGB-IEC61966-2.1 profile and the other color.org profiles identically, whereas some of the color managed image viewers I use don't - they have differing results.

So I extracted the sRGB-IEC61966-2.1 ICC profile from one of the offending JPGs using Argyll CMS tools and then inspected it with exiftool. It turns out that it is in fact a version 4 ICC profile. The reason I thought it was an Affinity issue is that all my other graphics packages export to JPG using a v2  ICC profile, not a v4 profile. 

Windows Photo Viewer (the colour managed version that comes from Windows 7, not the unmanaged Photos app that is the default in Windows 10) is known to have compatibility issues with V4 profiles, as do some other apps I would imagine. So this is clearly the cause of the problem...

Thanks for the help all those who responded to this thread. 

 

[Maarten Langeveld]

Apologies, I could not reproduce. My fault.

I'm having the same issues but I think it is not a v2/v4 ICC issue...

The cause is probably that when exporting an image in Affiny Photo with another colour profile, the colours aren't converted to the new profie but only the original colour profile is replaced by the newly chosen colour profile. That explains the weird behaviour.

From the help pages:

"By default, this is set to the ICC profile of the project (document). However, the project's ICC profile can be overwritten for this export area. Select from the pop-up menu."

I still cannot believe this is true since it makes the export function rather useless to me since I want to keep wide gamut in my working file and just export to for example sRGB for web publishing. Now I have to make a copy of the original work, save it, convert it to sRGB colour space, export (and then delete the converted work to save disk space). It is really unbelievable.

Also soft proofing wide Gamut images (i.e. AdobeRGB) with sRGB colour profile does not work either (it does work well with other colour spaces but not with sRGB, out of sRGB gamma colours are still clearly visible, in fact nothting changes).

Moreover my (very fast) PC crash often slows down to unacceptable levels or just crashes when soft proofing. I have been fairly enthuisastic about Affinity Photo but it crashes too often, the basics (colour management) are not well implemented (as mentioned above: exporting to another colour space is not possible, soft proofing wide gamut images for SRGB display does NOT work etc.).

[NotMyFault]

38 minutes ago, Maarten Langeveld said:

the colours aren't converted to the new profie but only the original colour profile is replaced by the newly chosen colour profile.

That is a bold claim which i cannot reproduce.

Please provide required evidence:

1. The source image
2. a screen recording of the procedure
3. the exported image

To simplify your live, please find attached a good test file: SRGB, RGB/8, contains all 16,7 Mio colors.

I exported it with DCI-P3 profile, and inspected the P3 file: identical colors.

When using RGB8, the process is unavoidably lossy: some colors are mapped to the same color values, which causes about 1/256 noise / loss per color channel

When converting to RBG/16, the process is lossless.

In Photo, you can simulate your claimed issue by assigning (not converting!) the DCI-P3 profile before exporting. The exported file will show wrong (not-matching to source file) colors.

 

[Maarten Langeveld]

See above. You are complete right. My apologies. I could not reproduce my claim about export function.

[Bobby Dee]

Hi, First time here. 

edited a few images in Photo and happy with the result. I then export either as a jpeg or tiff to my desktop so that I can drag it into Apple Photos so that I can use Whitagram app to post on IG. Suddenly they look flat and lose punch-any recommendations? Using latest Mac OS on a MacBook Air and Whitagram on iPhone XR

[BeauRX]

In looking into color profiles on my Mac, the management is not great. First the files can be located in multiples locations with different scopes and second the files names and internal profile names can be and are different. While not encountering a problem myself it is far from robust especially with multiple app installing their own profiles. This is even further complicated by multiple engines with what ever rules they have about where they look for profiles. Not sure if this is the problem but it doesn’t help.

[NotMyFault]

On 3/15/2022 at 12:13 PM, Bobby Dee said:

Hi, First time here. 

edited a few images in Photo and happy with the result. I then export either as a jpeg or tiff to my desktop so that I can drag it into Apple Photos so that I can use Whitagram app to post on IG. Suddenly they look flat and lose punch-any recommendations? Using latest Mac OS on a MacBook Air and Whitagram on iPhone XR

Hi and welcome to the forum. Sorry to hear about your issues.

We would need to get the following information from you:

• you OS, your display (exact model, exact mode selected)
• On Windows, GPU model, driver type and version, and GPU settings
• An document showing the issue
• screenshots of color profile settings for your display within OS
• Screenshot of your file opened in photo
• use channels panel and select R, G, B channels individually for display. You should see perfect smooth grey gradients from pure black to pure white (horizontally, vertically, …)
• please include the histogram, and the info panel. Place a color sampler over a pixel you think showing wrong color

if possible, set your display to sRGB, and set your document to sRGB profile (using convert, not assign).

this should give correct colors, and you can use your OS color picker tool to check if all color values match (between OS and Photo).

Please use this test image for screenshots. It shows all possible colors with RGB/8 documents. 

https://forum.affinity.serif.com/applications/core/interface/file/attachment.php?id=203060