XnView Software

Hi all,

With xnview 1.98.8 I have the following behaviour:

When repeating select all + copy + import (Ctrl-A + Ctrl-C + Ctrl-Shift-V), the greyscale image becomes darker and darker. I think the same happens if image is read and assembled into PDF (it is darker in PDF).

Initial file: test1.tif
After few copy-paste: test2.tif

Confirmed, this existed in 1.98.5 (the version I'm using) too. It seems to affect all 8bit images (although it's affect on 8 bit color images is very different from greyscale). It does not however affect b/w images, nor 24 or 32 bit images.
Also, it does not happen when you paste into an already darked image (even if the clipboard copy is new), but it will do it if you paste into a 24 bit image).

The image does not need to be greyscale on your disc, you can open any image & convert it to greyscale in xnview, then copy & import it. Reimporting the same clipboard image or a new clipboard image of the original pic will not increase the effect, but copying the darkened image & then importing that again will make it darker yet.

Strangely, the effect is magnified when you use fewer colors. The darkening is hard to spot with 256 greyscale, but is very dramatic with 32 greyscale. (Dithered & not dithered are equal, the number of colors is the key.)


Now.... If you want to see something from the 70s, do the same stuff with an 8 bit color image. Take a color image, convert it to 256 colors or less, then do the copy/paste bit you get a psychadelic rainbow effect. It actually looks kinda cool (if/when you're doing it intentionally).
The first pic is the original 24 bit jpg that I started with. After converting to 256 colors (no dither) and copy/pasting twice, you get the second pic.

Ok, i've find the problem...