[Solved] ColorSync: PNG file option "Reduce color depth if unused" if applied also fixing color profile accordingly ?

[porg]

We confirmed this works correctly: ColorSync: GC correctly ignores RGB color profile embedded into grayscale image

Followup question: GraphicConverter 's PNG file format options has the option "Reduce color depth if unused" (see screenshot below).

1) If that option is activated and GC on save detects that an RGB image has grayscale pixels only, and hence reduced from 24bit to 8bit, does GC also adapt the PNG file's color profile information accordingly?

2) Or could you end up with an inconsistent file "grayscale image with RGB ICC profile"? As the one I happened to have in the linked issue.

GraphicConverter PNG format option Reduce color depth if unused.png (39.89 KiB) Viewed 296 times

[forum_adm]

Thanks for your note.

I added now a sentence to the note into build 5667 (ETA 1):

[forum_adm]

I improved the dialog for build 5667.

[porg]

Great that you added help texts for "Reduce color depth if unused" and "Store ICC Profile". Now I feel much more certain what happens! I have some improvements for them:

Reduce color depth if unused

Last sentence "A color profile will not be saved" is still a bit ambiguous. Change to:

Will be saved without any color profile information. If it had one, that will be discarded. If it had none, no profile will be added either.


Store ICC Profile

In case of an sRGB profile no ICC profile will be embedded (ca. 1-8 KB) but only a "this is an sRGB" flag will be set (few bytes only).

[forum_adm]

Thanks for your suggestion. I will add it to the dialog.