On 28/08/2021 09:21, ?strid smith via cctalk wrote:
i've achieved satisfactory results paletteizing
scans of low-color-depth material using a tool called 'noteshrink':
Well as a guide the 66 page AA-CJ39A-TE (VAX-11 RSX Installation Guide
and Release Notes) is 8.8MB. That's with the front and rear cover
scanned as 300 dpi JPG and also 12 colour pages as 300 dpi JPG.
Each of the 600dpi PNG pages comes out at 26MB.
I tried optipng first. Even "-o 7" (which I ran overnight but I forgot
to time ...) only dropped a page down to 19MB. So completely impractical
for even this small number of pages.
Noteshrink (which I've seen before but never bothered to try!) knocked a
26MB PNG down to 700kB. The only issue is that the red looks quite a bit
more brown than it should. I'll look into it a bit more as it looks
antonio at acarlini.com