[metapost] defaultcolormodel

Hans Hagen pragma at wxs.nl
Fri Jul 8 23:50:26 CEST 2011

On 8-7-2011 11:24, Reinhard Kotucha wrote:

> Black, however, is well defined.  It's what you see if you are in a
> closed room and turn the light off.  This and the fact that color
> pigments used in black ink (inexpensive carbon) are nearly ideal, make
> RGB(0,0,0) ->  CMYK(0,0,0,1) a very good choice.  You don't see a
> difference between CMYK(0,0,0,1) and CMYK(1,1,1,1) though with the
> latter you waste a lot of ink.

I'm sure there is a difference between (0,0,0,1) and (1,1,1,1) ... black 
vs brownish.

> In LaTeX's color package, black is already CMYK(0,0,0,1), and this is
> also a good choice for Metapost.  Please note that with CMYK(1,1,1,1)
> you don't not only waste ink, the paper also gets too wet.

GRAY(0) is better, and also less code.

> All devices except printers and maybe nowadays 'electronic paper' are
> using an additive color model.  Hence, RGB wouldn't be a bad choice.
> But the gammuts are not necessarily the same.  There might be still
> differences on what is red, green, or blue.  Sensors might have their
> maximum sensitivity at different wavelengths.  You'll see this if you
> compare red LEDs from different manufacturers, for instance.

this is when color profiles kick in

> A better approach is to use a standardized color model and put the
> calibration data (color profiles) into the devices.  But then
> manufacturers have to agree on a standardized color model, which is
> unlikely to happen.

there are some standards


                                           Hans Hagen | PRAGMA ADE
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