[sane-devel] Random questions about Xsane

[m. allan noah]

On 10/17/07, Arch Willingham <arch_willingham at yahoo.com> wrote:
> We are trying hard to use Xsane (Fedora FC7 and FC8).
> We would appreciate any of these answers people could
> provide:
>
> *	What is the difference between grayscale, halftone,
> and lineart?
> *	When we send anything in color, the files become
> huge (one page is 9MB). What are some typical settings
> to change to scan a document with color and make the
> file a reasonable size.
> *	Often times when we scan something, the background
> is very gray. What causes that?

none of your questions are actually about Xsane. they are all really
about the scanner you have and the capabilites of the sane backend it
uses. neither of which have you included :)

but, your questions are fairly generic, so i will try to answer them.

1. grayscale is multi-level, usually 8 bit gray. half-tone and lineart
are both binary (black & white). half-tone uses a dithering mask to
attempt to achieve some level of gradation. google is your friend on
that one, but if you dont know what it is, you dont need it :)

2. 9 megs is nothing. i routinely make 100-200 meg color scans. if you
ask for color at any decent dpi, you are going to get lots of data. so
dont ask for color or high dpi if you dont need  it, and if you do,
try either compressing the image (gzip and bzip2 come to mind) or
convert to a compressed format like jpeg.

3. the scanner's read heads dont respond to light in the exact same
way as your eyes, compressing or stretching certain parts of the
spectrum. look for some sort of brightness/contrast or gamma controls,
often under the advanced settings, and highly scanner-specific.

allan

>
> Thanks!
>
> Arch
>
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