Oh, it has nothing to do with the version of ue4, as I pointed out in the “edit”.
This is always the case.
Migrating had nothing to do with it, I just happen to import the 8 bit versions afterwards.
(Next time I should probably refrain from telling a story before I get to the point)
I also noticed that I made a typo in the previous post causing confusing, so…
- get a random texture.
- save one version as 16 bit png.
- save another one as 8 bit png.
- import both.
- already see the result, the 16 bit png is washed out. (srgb is automatically activated)
- disable SRGB on both:
conclusion: 16 bit png is washed out,