[Tig] Neophyte with calibration questions

Richard Simon rlsimon
Fri Apr 25 19:29:03 BST 2003


I work for a small visual effects/post-production shop and I've recently
been tasked with dealing with our color calibration issues for our
computer monitors. I have done a small amount of research on line and
read through the archives of sci.engr.color.  I also looked through the
archives of the TIG, but did not see some answers to some of my
questions and Rob suggested I revive the topic on the list. I am new to
most of this, so I apologize if some of the information I'm looking for
is rather basic.

We do mostly film work and are trying to get the monitors to display
scanned film frames with as much fidelity as possible.
In pursuit of this, we purchased an X-Rite DTP-92 colorimeter and
Pantone's OptiCAL software.  This gets us a very basic calibration, but
the degrees of freedom left unconstrained seems larger than the number
that get fixed by the process.  Some questions that have come up:
1. What is the standard whitepoint for film? we have been using 5400K
(handed down from the mountain by an ancient and no longer remebered
sage who worked at the company) but is this good? I have seen lots of
opinions, but no hard facts or criteria for judging the right standard.
1a. what luminance value should I have for pure white?  It seemed like
D65 specified Y=100, but is that also the case for film?
2. How should I measure and set the black levels?  on some monitors the
luminance is too low for the colorimeter, so what level of gray is a
good one for measuring at the bottom?  
3. Should the chrominance of my gray be the same as my white? should it
be the same all the way to black? 
3a. what should the luminance values be at these levels?
4. what are the other significant obstacles to getting our monitors to
look like each other?  
5. what are the other significant obstacles to getting our monitors to
look even remotely like film?
6. Are Barco monitors worth the purchase? Is there a better color
reference monitor that we should look at?
7. I have a firm belief that we can establish a measurable process for
doing our calibrations and we should be able to use instruments and
numbers to verify if our monitors are good. Am I an idiot?
8. are there books, articles, papers that can offer more insight into
these issues?
9. Are there businesses out there that offer services to do what we need
to our monitors?

Thanks in advance for any help any of you can give me with any of these
questions.




Richard Simon
Giant Killer Robots
576 Natoma St.
San Francisco, CA 94103
(415) 863-9119






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