How custom palette is defined in PNG export?

[MxHeppa]

How custom palette is defined in PNG export?

[NathanC]

Hi @MxHeppa,

The 'Custom' palette function within the export settings unfortunately doesn't currently work and will always result in an error when attempting to export with it set from the dropdown, this is logged with the developers but needs updating to reflect the fact that it affects v2, I've bumped it with your report.

From what I've read I believe it creates a PNG using just the palette of colours used in the document, but it's difficult to give specifics when the function doesn't work.

[MxHeppa]

sounds good this way if i have selected palette with speffic colours exports with them and i mean when it work. luckily such special cases i can do way i scale etc image in Affinity Photo and use end platfrom tools convert image to speffic palette. my need is related old school machine (Amiga without graphic card) wallpapers.

[TravisL]

I'd like to add to this and say I have a situation where I have very large images with transparency required for a web design and I need to be able to control the bit depth and dithering to reduce the file size. That the palette function does not work and creates completely blank images when attempting to use it on an image with transparency is an oversight and I hope that this is fixed in a future update. A good system I've found is Image Demon (a free program) which lets you control the dithering algorithm and amount of dithering.