Re: Display Profiling
Re: Display Profiling
- Subject: Re: Display Profiling
- From: Robin Myers <email@hidden>
- Date: Tue, 20 Mar 2001 04:55:56 -0800
- Organization: Robin Myers Imaging
>
c. Apple ColorSync 1.0 only supported matrix-based conversions for
>
all device types including printers, making ProfileMaker 1.0 a tad
>
limited -:).
Be very careful here not to imply that monitors and printers were treated the
same. ColorSync 1 did use matrices for printers and scanners, however, it was not
the same method as those used for the monitors. It used six matrices for printers
(twelve in the good stuff that the public did not get), coupled with preceding
linearization tables and following adjustment tables. You can see all the details
on the U.S. Patent and Trademark database www.uspto.gov (sorry, I do not have the
number close to hand). Also, if the monitor has been calibrated in the video
lookup tables to produce a given gamma curve, then a simple matrix is an accurate
description of the video response and as accurate as a table lookup (depending on
the bit depth of the adjustment tables and the desired gamma equation [there are
more than one]). On several of the technologies available at the time, the
results could be quite accurate (ink jet, wax thermal transfer, printing press)
or not in the case of dye diffusion thermal transfer (aka dye sublimation or
D2T2) [both assuming using the never made public 12 matrices code described in
the patent].
Robin D. Myers