Here is a "paldemo" 0-255 palette display program that uses the new "geekmaster formula 42" version that balances the number of pure blacks and whites in the palette, for all kindles:
https://www.mobileread.com/forums/sho....php?p=2050759
FYI, the display palette onscreen size is adjustable. In the example, palette(550) is used for a 550x500 pixel palette.
EDIT: Be sure to read the text about display gamma in the screenshot spoiler at the above link. This is especially important for converting desktop display images to kindle eink images, like VNC needs to do. I just updated that "display gamma" information, so if you already read it before the "last edited" timestamp on this post, please go back and read it again.