Re: Scanning problems

[Doug Craigen <dcc@ESCAPE.CA>]

Leigh Palmer wrote:
> I would like to post my lecture transparencies to the web for my
> students' benefit. A problem arises when I use color; the files are
> too large when I scan them in mindlessly using the software that
> came with my scanner. It will handle "line-art", presumably one-bit
> intensity resolution, or "gray scale", presumably eight-bit, or
> "color RGB", presumably 24-bit (or maybe even 32). For my purpose it
> would be both adequate and desirable to have four-bit color.

Leigh, how to handle this depends a lot on the software available.  I
use Paint Shop Pro for most of my graphical work.  For dealing with
handwritten notes I scan them in then reduce the color to black, white
and one shade of gray.  That seems to provide reasonable resolution (the
one gray shade gets rid of the really bumpy appearance of "line-art"
which is just black and white).  Since you want to retain some color,
what you would do within PSP - and you can see if your own software
permits the same thing - is to define the color palette you want used
for color reductions (you may even be able to apply this palette to the
scan directly).  For nice-looking but small size files I would save them
as gifs, but you might try ignoring the color depth issue altogether and
try saving them as jpgs under various compression factors to see if you
can come up with a size and appearance that suits you.


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Doug Craigen
          Latest Project - the Physics E-source
          http://www.dctech.com/physics/