[Some comments on the scanning of public domain books at end.]
Correct, that's the idea.
http://www.targets.coloraid.de/ is a source for good quality, yet
reasonably priced 'IT-8' targets, including reflective versions.
They come with a reference file that gives the actual colors, but at
a predefined reference spectral illumination. You'll need an
application that can build a profile based on a standard
illumination level and as little postprocessing as possible.
Thanks! I should have realized the role illumination level plays on
color reproduction. *slapping hand on head*
At the risk of attracting the resident VueScan basher :-(, VueScan
(professional) <
http://www.hamrick.com/vsm.html> allows to build
profiles with such an IT-8 target, and probably can drive your
scanner as well. The profiles are of a simplified type, but will get
you close to the result you want.
Other options include experimenting with Little CMS
(
http://www.littlecms.com/).
Thanks for the informative feedback.
****
Now, I'd like to address the reply from "bmoag" by providing a little
more background to my initial request.
My interest with color calibration is to setup a local "distributed
scanning" group to scan public domain books, and do so in association
with the Internet Archive and OCA (now talking with Brewster Kahle.)
It is likely we'll start off using the fairly inexpensive Plustek
OpticBook 3600 which can do bound books. Page scans will be at 600
dpi, 24-bit color, and losslessly compressed, burned to DVD-ROM and
sent in to IA as well as archived on our end (some illustrations we
might go as high as 1200 dpi.) Later on, after we better understand
the real-world work flow issues and become comfortable with our QA
procedures, we may get a professional-level sheet feed scanner to do
books which can be chopped -- this should greatly increase our
throughput. Of course, the Internet Archive has developed the Scribe
scanner, which uses digital cameras rather than a flatbed arrangement
for scanning, and if our group thrives, we may add that scanner, or
something similar like the Atiz, to our fleet of scanners (thus my
interest in geometric lens distortion issues.)
Obviously, in a volunteer group setting like this, using multiple
scanners, we need to color normalize our scans, or provide the means
for someone else to do so by including scans of a standardized color
target along with each book scan set. For our scanning workflow, the
approach I'm thinking of is to scan the color target first, then scan
the book pages, then rescan the color target at the end of the job.
The color target scans will always be included with the book's raw
scan set.
One issue we have, of course, is QA. And one QA item (among several)
is if a scanner has technical problems. This should be seen by our
QA volunteers when they look at the scan of the color target. If too
dark, or the colors are obviously way off, or there's "banding" across
the solid color areas, means the scanner is having some kind of
problem, or the person scanning may have used the wrong scanner
settings.
We don't initially plan to cleanup ("restore") the raw page scans,
which includes color normalization, deskewing, cropping, etc. That's
for another volunteer group to do (anyone here want to volunteer to
set that up and lead it? <smile/>) Certainly having a scan of the
color target for each book set will aid with both QA and with color
normalization.
Now, one has to remember that in a volunteer setting with "amateurs",
many of whom are not trained Rocket Scientists (tm), we have to
minimize as much as possible all the technical details they have to
contend with during scanning -- they will have enough on their plate
as it is. Keep this in mind if you decide to reply with suggestions of
your own (of course, suggestions are welcome!)
Thanks.
Jon Noring
(p.s., yes I'm aware of the large-scale scanning activities taking
place. After all, I'm in contact with Brewster Kahle at IA, etc. So
don't bring this up -- there is interest in trying the "distributed
scanning" idea for reasons off-topic to this group.)
