[OT] Scanning

[Thomas Pryds Lauritsen]

timo ronkainen wrote:
> This is pretty good for printing, but tiff would be better format, if 
> you want it to not to loose any data.

Even better for compression without losing data is PNG. It typically
produces a smaller file than TIFF, but of course still larger than JPEG.

In my experience you can split images into two categories:

1. Images with many variations in colours and shades, e.g. photos and
"raw" scans.
2. Images with large, uniformly coloured areas, e.g. a scan that has
been through a tool like ComicIt(*) or similar filters, or computer
generated graphics.

For web, in most cases I'd recommend JPEG for type 1 because PNG tends
to produce large files for this kind of image (and for web you need
small files) and because you can live with small amount of artifacts
caused by lossy compression. Still for web, I'd recommend PNG for type 2
because JPEG compression artifacts tend to be more visible here and
because PNG performs better with images of type 2 than type 1.

For (high quality) print I'd recommend PNG for both types of image since
you probably don't want any artifacts at all.

<AD>
(*) ComicIt is a tool for Windows 95 and above that removes the
variation in shade from areas that should really have been in one shade.
You can get it from http://raptus.dk/free-software/comicit-1.0-win95.zip
<AD END>

-- 
Thomas Pryds Lauritsen
http://www.cs.aau.dk/~pryds/

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