How to embed an sRGB profile with g=1.0 after GC conversion

[forum_adm]

I don't understand the problem.

Any gamma change within GraphicConverter is directly applied to the image pixel data. The color profile stays the same.

The gamma value inside PNGs is legacy and should no longer used. Color management should always be done by a color profile.

What is your exact workflow?

[es]

Ok, let's try this simple example, maybe it will clear things up:

Create two new files with GC with the following settings

1. 1st file: 16b with the built-in sRGB profile

   

   1'sRGB built-in'.png (50.01 KiB) Viewed 328 times

2. 2nd file: 16b with the a 'sRGB Gamma=1.0' profile

   

   2'sRGB Gamma=1.0'.png (50.99 KiB) Viewed 328 times

3. Now in each file add Core Image Filters → Linear Gradient from pure green to pure red.
   They look the same!
4. Save these files (due to 3 image forum limit will post them in the following message) and reopen them
   Now the look different!

The second file is darker because it's reopened with the default sRGB profile, not with the linear light profile! So the information that it was created with g=1.0 is lost

[es]

The two files with linear gradients added
1st file

1 48bpc sRGB built-in, Linear gradient G→R.png (7.43 KiB) Viewed 328 times

2nd file

2 48bpc 'sRGB, Gamma=1.0', Linear gradient G→R.png (7.24 KiB) Viewed 328 times

So do you think that when saving the second file created with a "non-sRGB" profile GC should've embedded it to preserve the difference in gamma value while still not embedding the proper sRGB profile (not to waste space)?

[forum_adm]

Ah - now it is clear.
Can you please forward the gamma=1 profile to support@lemkesoft.de ?

[es]

Sure thing, see the attached zip, it was in "~/Library/Application Support/GraphicConverter/Profiles", but then I guess your app just saves various profiles it encounters there (I initially thought that it was one of your default profiles added on install)

[forum_adm]

Please recheck with build 5699. It checks now the estimated gamma value if sRGB is detected.