[Printing-architecture] Questions, Concern, Disscusion on CPD

Hal V. Engel hvengel at astound.net
Fri Jul 10 16:00:36 PDT 2009


On Thursday 09 July 2009 09:39:14 am Petrie, Glen wrote:
>  E: Another "option" to consider for this section is an advanced button.
> The key to printing a specific print-quality (actually, better stated as
> a specific print-intent) is to know more about the media being printed
> to.   That is, for example using paper; what is brightness, the weight,
> the finish (rough, smooth, polished), color, etc.  From these facts, the
> printer driver can tune its color-to-ink processing and other factors to
> achieve the best output for the user print intent.  Typically, a user
> can easily find this information on the cover of the media being used in
> the printer.  Note, I have not seen this kind of processing done in
> color-management processing software.

You are incorrect.  This is exactly what should happen in a proper color 
managed work flow and this is exactly what color management is for.  Proper 
profiles are media (as well as device and device settings) specific.  They are 
created by measuring the media white point (you called this color) and 
brightness (these are actually the same thing) as well as the resulting 
absolute (meaning CIE XYZ or CIE L*a*b*) colors/tones of various amounts and 
combinations of inks/colorants on that media (we usually measure 1,000 to 
3,000 color patches when creating a printer profile).  

The correct use of a printer ICC profile should optimize how the 
inks/colorants are put down on the paper to match the paper white point to the 
grays/blacks created by the inks/colorants (I have assumed relative 
colorimentric intent) as well as to optimize the gamut/dynamic range of the 
resulting prints without over inking.

I am not sure if I have ever seen a paper package that had the media white 
point listed at least not in a form that would have colorimetric meaning.  
Although these may exist I have NEVER seen a printer driver that had the 
ability to accept this data (paper white point) as user input other than by 
using an ICC profile.  I just looked at the box and the product sheet from the 
box of the Ilford paper that I use and it did NOT list the paper white point 
or brightness of the paper.  If it did I would expect to find something like:

White point: XYZ: 84.550000 88.240000 74.960000, D50 Lab: 95.261904 -0.999796 
-1.888369

(The above is the measured white point of a sample of Ilford Galerie Smooth 
Gloss paper - note the first Lab value is also the "brightness" - actually 
Luminosity - of the paper).

Isn't the media type setting what is used to denote the general 
characteristics of the media such as finish and weight.... 

Hal 


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