Premultiplied display mode
Posted: Wed Sep 18, 2024 3:09 pm
Some files (EXR specifically) often contain color in a premultiplied format. It would be nice if XnView had an option to display them as such. Currently, a fully-additive premultiplied EXR (e.g., containing only an additive fire in color but a fully transparent alpha channel) is displayed as fully transparent.
I'm attaching an example image. It contains a fire with very transparent alpha, but a lot of glow in RGB. It should be drawn as very bright mostly-additive (but partially opaque, too). Instead, it's displayed by XnView as barely visible and very dark (a well-documented effect of double pre-multiplication).
How it should be displayed:
The current XnView behavior:
Preferably, there should be:
I'm attaching an example image. It contains a fire with very transparent alpha, but a lot of glow in RGB. It should be drawn as very bright mostly-additive (but partially opaque, too). Instead, it's displayed by XnView as barely visible and very dark (a well-documented effect of double pre-multiplication).
How it should be displayed:
- What SHOULD be displayed
- _right.jpg (35.37 KiB) Viewed 576 times
- What's actually displayed now
- _wrong.jpg (34.48 KiB) Viewed 576 times
- a per-file-type premultiplied/un-premultiplied display-mode association, with most (or all) of the files being associated to "un-premultiplied" mode by default (and only EXR and, maybe, TIFF being set to premultiplied);
- a hotkey to switch this mode on the fly.