Colorspaces and medium interactions

Leonardo Giordani leonardo.giordani at
Thu Mar 30 10:55:02 CEST 2006

While I'm working on the implementation of Curtis's paper (watercolors), I was 
wondering what a colorspace is supposed to contain.

Namely a colorspace is a reference system that let the user identify colors in 
the spectral space: according to this RGB, CMYK, Lab, etc, are colorspaces. 
Watercolors (Curtis's, Levien's, Wet and sticky) aren't colorspaces: they 
contain a colorspace, but also other functions such as drying, edge 
darkening, etc. Generally speaking they contain "behaviour" functions.

So what we call colorspace is something more general, a composition of 
physical behaviour and colorspace.

RGB, CMYK, Lab and so on are colorspaces of the "flat" medium (so to say), 
becouse they simply "paint" the medium, they change the color of the medium 

Wet and wet&sticky are "watercolor" mediums and their have only one 
colorspace. They interact with the medium in a complex way, for example 
wetting it, releasing pigment according to its height, etc.

So my proposal is to re-structure the current "colorspace" directory in order 
to show this difference and to introduce methods that implements the 
interaction with the medium.

This way RGB and friends could simply inherit the standard interaction methods 
(thus not changing), while watercolors and other fancy things will redefine 
them. The users could select the kind of paper he prefers (by weight, shine, 
pattern, etc.) and let the color interact or not with it.

What do you think about this?


Leonardo Giordani

Tele-Rilevamento Europa - T.R.E. s.r.l.
a POLIMI spin-off company
Via Vittoria Colonna, 7
20149 Milano - Italia
tel.: +39.02.4343.121
fax: +39.02.4343.1230
e-mail: leonardo.giordani (at)

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