Re: Monitor Calibration Quality Evaluation Protocol
Re: Monitor Calibration Quality Evaluation Protocol
- Subject: Re: Monitor Calibration Quality Evaluation Protocol
- From: <email@hidden>
- Date: Wed, 22 Jun 2005 12:57:25 -0400
Hello Edmund,
I have suggestions on two aspects of what you are asking
for.
1- For monitor calibration, LCD or CRT, there is the ISO
3664 standard that specifies, for color monitors,
brightness, brightness uniformity, chromaticity, and
Correlated Color Temperature and White Point. It just
happens that my company launched a product, two days ago,
to do that (and a few other things) using the Eye-One
(good thing you have an Eye-One!). You may also want to
add contrast to these measurements.
2- To use a ColorChecker means using appropriate reference
data. It also just happens that I personnally spent quite
some time gathering ColorChecker data sent by many
internet fellows and computing their average (hint: more
data welcomed). I just updated the freely downloadable
data based on more charts (images in many formats and RGB
spaces, and data, including spectrums, in a spreadsheet).
(Note: this is separate from the product mentioned above.)
As for measuring the charts, the free MeasureTool was
available at one point to do that. Others could confirm if
it can still be obtained.
Finally, for the question of suitability of the Eye-One
for this task, I can only say it is more than enough.
Obviously, I may be biased a bit, but I saw a lot of data
coming from various Eye-Ones and other spectros of similar
types (X-Rite and GMB), and its matches quite well. You
would not have much data sent to you if you specified a
higher precision instrument, and for marginally better
results.
Regards,
Danny Pascale
dpascale AT babelcolor DOT com
www.BabelColor.Com
On Wed, 22 Jun 2005 17:33:55 +0200
edmund ronald <email@hidden> wrote:
Hi, folks !
As you know, I write a fair bit about color management,
and I'd like
to get my opinions about LCD monitor calibration on a
more solid
footing. So, I would like to establish a test protocol
that I could
run on my machines to test calibrators. This is
journalism, not rocket
science, but I still want to be able to do things
decently.
I was thinking of first adopting a methodology similar
to that of Dr.
Abhay Sharma for the WMU profiling review,
http://www.wmich.edu/ppse/staff/downloads/index.html
This means doing a whitepoint measurement and then
computing delta E
for colorchecker squares. The evaluation results can
then be the avg
and max delta E measured.
The instrumentation I now have is a Gretag Eyeone
spectrophotometer. I
wonder whether this would be sufficient to act as a
reference for this
purpose, seeing I'm doing journalism and not science?
Also, I don't
know how to do the reading: Which software can put the
instrument in a
state to read in the screen squares, then make
measurements ? I guess
I need to somehow establish the base 100L value then
compute the delta
E for each colorchecker square, can anyone tell me
exactly how set up
software to do this ? It would be nice if Gretag offered
some support,
eg. made their SDK available ...Maybe some existing
package can
already do this ?
Specialists will rightly assume I don't know what I'm
doing; however,
Color Management is now trickling down to consumer level
so we need
consumer-level testing of this type.
I am cross-posting to my photofeedback blog, at
http://photofeedback.blogspot.com so you can answer here
or comment
there if you wish. I would appreciate input from all the
professional
members of the community.
Edmund
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