Herman,
A long time ago, I experimented with the same idea, having pencil color
illustrations to scan.
I never completed the project by I got the point of creating a "target" made
with squares I colored by hand using the wood crayons (German-made
Polychromos). I had patches for all 64 colors and patches for tints and
shades and combinations of each crayon color. Next, I was suppose to measure
them with a spectro to build a "Reference file".
I never got to it...
I have the chart somewhere in my office but can't find it this morning.
Wish I could show you...
MfG / Roger
@Graeme: is it OK I use "MfG"?
-----Original Message-----
From: argyllcms-bounce@xxxxxxxxxxxxx <argyllcms-bounce@xxxxxxxxxxxxx> On
Behalf Of Hermann-Josef Röser
Sent: Thursday, February 11, 2021 8:56 AM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] ICC-profile for drawings / paintings
Hello,
in the German scanner forum it was asked how to achieve device-independent
colours for scans of drawings / paintings.
I made a brief test with a drawing with colour pencils one of my
grandchildren did. I scanned it and then used an ICC-profile derived from a
reflectance target on Kodak film to render the scan. The colours that came
out were not correct. Presumably, since the target did not match the paper /
pencil combination.
Now I wonder, how to improve -- just out of curiosity. My idea is to draw a
target on the dedicated paper using these pencils, e.g. like the x-rite
color checker classic. One can use a spectrophotometer and measure the
reflectance spectra of the patches and calculate the XYZ- and Lab-values for
D50 using the formulae given e.g. by Bruce Lindbloom. So one could create a
reference table for this "target" and scan the "target".
But how would one then proceed with Argyll, since scanin will most likely
not recognize the hand-made target fields? I could manually measure the R,
G, and B-values and their standard deviation of the patches with imageJ and
edit a ti3-file. Would that be it?
Many thanks in advance and best wishes
Hermann-Josef
