Re: [gentoo-user] Re: [OT] Re: PDF: convert to grayscale

[Willie Wong <wwong@math.princeton.edu>]

On Mon, Feb 28, 2011 at 03:08:23PM +0000, Grant Edwards wrote:
> > That makes me wonder... in a color printer, I expect it not to print any
> > color when it has no color ink, but do grayscale printers apply some
> > conversion internally, to make sure that e.g. plain cyan is still
> > visible (instead of making it white)?
> 
> No.
> 
> No matter what transformation you use from a 3-dimensional space into
> a 1-dimensional space, there will be sets of values that differ in the
> 3-dimensional space which map to identical values in the 1-dimensional
> space.

But it is trivial to make a transformation that maps to certain sets
of values not more than once. In particular, there's nothing barring
the printer to make it so that only pure white and pure black gets
mapped to white and black, and everything else maps (nonuniquely) to a
shade of grey. 

W
-- 
Willie W. Wong                                     wwong@math.princeton.edu
Data aequatione quotcunque fluentes quantitae involvente fluxiones invenire 
         et vice versa   ~~~  I. Newton