[100632] in RedHat Linux List
color fixer-uper (after scanning) & color calibration & tuning.
daemon@ATHENA.MIT.EDU (Jan Vicherek)
Sun Nov 22 14:03:00 1998
Date: Sun, 22 Nov 1998 14:02:27 -0500 (EST)
From: Jan Vicherek <post-only@ied.com>
To: RedHat mailing list <redhat-list@redhat.com>
Resent-From: redhat-list@redhat.com
Reply-To: redhat-list@redhat.com
Hello,
This question is about scanning, color calibration and automatic
adjustment of color/bringhtness/sarutarion/etc/... of the scanned image.
First of all, if you know of a better mailing list / newsgroup to send
this to rather than redhat-list@redhat.com, please do let me know at
honza@ied.com (or reply to post-only@ied.com).
I have a Microtek ScanMaker E3. It's about two years old, I think.
Lately I've decided that I'll scan in some pictures (some art works).
The outcome of these pictures is color-sensitive -- i.e. it is important
that the colors and bringhtness and all that stuff matches on the screen
what is on the photo.
However, it seems that the scanner is decaying -- it produces darker
and color-imprecise images. I've tried to play with various settings
[-s,-l,-m,-d,-e,-k,-G] of the scanning program (man mtekscan), but the
only option that I had any success with was -G (gamma correction) option.
However, while I was able to achive some positive effect with it, much
of the spectrum was quite off. I concluded that gamma correcting on the
scanner is not going to match all colors the way I need.
So I scanned it into xv :
mtekscan -G 2.4 1.7 1.5 -f 0 0 4 5.875 -c | xv -
and started playing with the color editor. After a half hour, I had a
result on my screen that looked pretty much like the photo. Then I
realized, that there was no way to save the color adjustment info into a
file under xv, so I would have to go manually through all 300 pictures.
Ugh. I don't think so.
Then it occured to me (duh) that it looks right on *my* monitor &
videocard (65k colors). So I tried it on another workstation. (65k colors
too). Of course, the result was altogether different.
This whole process has created the following questions (in order of
importance) :
1. is there a program(s) which would let me do :
$ interactive_program_Iam_looking_for sample.picture.ppm
# now edit the colors
# now save the color adjustment values into "coloradj.file"
$ program_Iam_looking_for -option "coloradj.file" <picture.223.ppm >corrected.picture.223.ppm
# it is highly desirable that the second step requires no human interaction
2. what are the resources and the procedure which would let me
calibrate my monitor to a *standard* ? I realize that the human eye is not
perfect and is not able to quantify color precisely, so I don't expect to
get my monitor *perfectly* calibrated, but there may be tricks and simple,
easily reachable inexpensive tools that I'm not aware of, which would let
a layman adjust her monitor to get a better approximation on their monitor
to what the picture looks like in reality. I.e. "color-calibration" of
one's monitor.
3. is it normal for scanners to get "weak" as time ellapses ? I.e. it
seems that my scanner produces darker pictures than it used to.
Thank you very much for any answers,
Jan
-- Gospel of Jesus is the saving power of God for all who believe --
## To some, nothing is impossible. ##
http://Vicherek.Waterloo.on.ca/
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