Daniel Pfeiffer wrote:
Hi,
Post by Daniel PfeifferIn Profilemaker Profile-Editor, there is a option to alter the white point
of icc-profiles. Somethimes, this can be useful if a different stock of
paper comes with a slightly more or less yellowish tint without
re-profiling the substrate. To do so, I take a number of readings on the
stock, average the results and enter them as new white-point. This helped
me in the past for some minor substrate-issues.
Hmm. I wouldn't expect that to work very well, unless you are using
the profile in absolute rendering intent mode. The reason is
that by default the profile will be white point relative, so
any slight shift in substrate color will tend to have little
effect on the result.
[ I did write a tool to more accurately shift the substrate color
and other print process characteristics of a set of measurements using
spectral reflection decomposition, but haven't at this stage released it. ]
Post by Daniel PfeifferThe other thing i'm thinking about is to reduce the number of patches in
testcharts when profiling substrates like ceramic, glass or textiles.
On objects like bottles, cans or boxes with very little space for printing
charts on, i would prefer to take multiple spot readings on black and
substrate to enter them before or after the profiling process rather than
waste space for redundant b/w patches in a test chart.
For creating profiles with an absolute minimum number of patches,
then a radically different profiling approach is really needed, one that
models the underlying physics more closely, rather than simply
measuring the device response in great detail.
You can try such an approach with the ArgyllCMS tools by making use
of the MPP profiler. You could try a quite small number of test patches
(16 - 100 patches), create an MPP profile from that set, and then
convert it to an ICC profile by:
Creating a dummy .ti1 of test points (5-10000 points)
Using fakeread to create a .ti3 file from the MPP
Create an ICC profile in the usual way.
Graeme Gill.