PNG8s are always tagged as sRGB irrespective of options or actual colour space

[paperboyo]

Hello,

Thanks for the great tool! I’m testing Generator to replace some SFW scripts used to output CMYK imagery to PNG. Unfortunately, SaveForWeb is buggy when it comes to controlling the conversion to sRGB and embedding the profile...

In latest Photoshop 2015.5.1 (latest Win10), pngquant seems to be the default (contrary to wiki).

Irregardless of whether the options to embed ICC profiles are set through the Export As UI or through generator config file (or its absence), and irregardless of how they are actually set (to embed or not) - the output PNG8s always contain sRGB (and gAMA) chunks! That happens not only when one specifically sets the options to not include the profile on output, but also (sic!) when the image is not in the sRGB colour space at all (e.g. in ProPhotoRGB).

As a side-note, and to confuse things even more, latest Photoshop is not able to properly recognise sRGB PNG chunk in the files it writes so these PNG8 files open as Untagged RGB. PNG24 in sRGB are bloated with 2,6KB of iCCP, so they are recognised properly (but are bigger than necessary).

I’m not sure if pngquant shipped with Photoshop is compiled with colour management as the version shipped (2.1.1) is too old to print this info (warning starts with version 2.5, current version is 2.7.2).

Regards
m.

[kornelski]

Since v2.6 pngquant can generate untagged files.

[paperboyo]

Problems still unfixed in 2017.0.1. Would this issue be more appropriate for reporting in https://github.com/adobe-photoshop/generator-core?