Digital BW, The Print

In a message dated 5/8/02 3:59:23 PM, jrandall@... writes:

>Aren't all the RGB partitioned curves (and the lumped RGB curves as 
>well) really just specific paper/inkset profiles with the color 
>(grayscale in this case) mapping values stored in three continuous 
>transfer curves (R,G,B) rather than as descrete values in a color 
>look-up table? 

Now heres someone who knows the true difference between 2d curves and 3d Look 
Up Tables! Always nice to find out someone is fluent in this stuff. The added 
advantage of the 3d LUTs are for correcting localized variations 
(non-linearities) that can't be reached by any one channel. In color terms 
(since its much easier to visualize than the gray inks) this means that if 
the medium saturation orange tones are too dark, or to saturated, or too red, 
that one specific area can be adjusted in an ICC profile, while a set of RGB 
curves could only make changes that would effect all reds or all yellows or a 
given lightness, no matter the exact hue or saturation. 

C. David Tobie
Design Cooperative
CDTobie@...