Subject: RE_Scanner profiling, Screen Cezanne
Subject: RE_Scanner profiling, Screen Cezanne
- Subject: Subject: RE_Scanner profiling, Screen Cezanne
- From: Randy Zaucha <email@hidden>
- Date: Sat, 14 May 2005 14:02:16 -0700 (PDT)
- Comment: DomainKeys? See http://antispam.yahoo.com/domainkeys
Pardon the blast from the past but there is another
way to calibrate/profile a scanner...
Back in the dark pre-digital ages when all scanners
had drums and six figure price tags, scanners were set
up manually with the available interface controls and
color charts/images. As an employee of a scanner
manufacturer, I was dispatched to scan gray scales and
color charts, adjust them to the proper scanner
values, output the images as film and proof them. The
interface settings were fine tuned until there was a
close match between scanned original and resulting
prepress proof.
The interface settings were saved and used as a
starting point for all scans for that particular image
type. (reflective, transparency, Kodachrome,
Ektachrome, etc.) Tone, gray, color and even sharpness
settings were recorded (like ICC profiles but in
analogue form) for various original types, formats and
output sizes.
Simply put, a profile is a summary or outline of data.
While using a spectrophotometer and color management
software is a better (faster & more accurate) way to
make a scanner profile, most scanner interfaces can
create a profile of the scanning device and make it
see more like the eye does. That of course is the goal
of profiling a scanner.
So the Cezanne owners could use the scanner's software
(probably not designed by a Color Genius) to profile
the device. They can use the specific patch values
supplied with their IT8 charts (in the reference file)
as numeric aimpoints. The trick is to first set the
scanner's tone controls for the light to dark patches,
then gray balance for the RGB balance of those
patches and finally hue adjustments for the colored
patches to program the scanner to output the proper
color values. Save the new interface settings and use
repeatedly. Or...you can bypass most of the interface
controls and use the curves and selective color
correction menus in Photoshop. Then you can set up an
action script to apply those adjustments. If you aim
for Adobe RGB values and assign that profile,voila...
color managed scans without ICC profiling software.
To let the cat out of the bag, I have developed a
scanner profiling product that uses this manual
procedure to profile any scanner. This method
(zbetterscan.com) comes with a custom color chart and
is designed for non-color experts who just want good
color without all the rocket science.
I'll be making a formal announcement about my product
on the list next week. Right now I'm waiting for a
couple reviews and a web page update to happen.
In closing, it has always amazed me how scanner
interface designs have been dumbed down and over
simplified (but without ICC profile interaction) since
the advent of desktop publishing. Still, the majority
of color error in the reproduction process usually
comes in the image digitizing stage so getting an
accurate scan is the most important step to getting
good color for any use.
Randy Zaucha
Media Arts Group
ZBetterscan Method
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