[texhax] CMYK (WAS Re: dotfill leaders on first line of paragraph only ?)

[Pierre MacKay]

On 12/11/2011 6:38 PM, Reinhard Kotucha wrote:
> On 2011-12-11 at 12:07:45 +0000, Philip TAYLOR wrote:
>
>   >
>   >
>   >  Reinhard Kotucha wrote:
>   >
>   >  >  Ok.  Red could be a little bit darker.
>   >
>   >  I have no experience of working in CMYK, and even
>   >  less of specifying colours in RGB and then mapping
>   >  them to CMYK ...  Given that this particular red
>   >  is specified as :
>   >
>   >  	\font \whatever = "Palatino Linotype": color=FF0000
>   >
>   >  which then gets re-written in TeX as :
>   >
>   >  	\whatever (macro) ->  \font:whatever \modemagic \special {color push cmyk 0.0 1.0 1.0 0.0}
>   >
>   >  how would you suggest re-writing "color=FF0000" to
>   >  achieve a darker CMYK red as you suggest.  The algorithm
>   >  on which the code is based is at :
>   >
>   >  	http://www.javascripter.net/faq/rgb2cmyk.htm
>
> I suppose you have to omit the color specification of the font. It
> seems that only RGB is supported.  You have to use \special instead,
> as described by Heiko already.
>
> Select a color here
>
>    http://www.tabelle.info/farben_pantone_CMYK_RGB.html
>
> and divide the values by 100.
>
>   >  >  The last step is to choose a
>   >  >  good type of paper and avoid lamination.  Laminated menu cards are
>   >  >  only good for fast food restaurants.  They always look cheap.
>   >
>   >  I am afraid that Thai-An is not yet in the same league as
>   >  La Tour d'Argent, or even Le Manoir Aux Quat'Saison --
>
> Ok, not yet.
>
>   >  lamination (tri-fold, gatefold) is the order of the day.
>
>   >  >  Menu cards printed on plain paper look more more elegant.  You
>   >  >  need more copies then, but you also save the money for
>   >  >  lamination.
>   >  >
>   >  >  Paper looks more elegant if it's a bit brownish instead of white.
>   >  >  However, I fear that you don't have much freedom here because
>   >  >  people expect that rice is white.
>   >
>   >  You mean there's no true white ink in the CMYK process ?  Useless !
>
>    http://en.wikipedia.org/wiki/CMYK_color_model
>
There seems to be some misunderstanding of the sense of ``CMYK 
process.''   The use of CMYK  implies the use of ink,  Wet, sloppy ink.
The process is a way of getting predictable results on a display screen, 
or when there are a limited number of color pens on an ink-jet printer.
In CMYK, white is specified as the COMPLETE absence of ink.  [0.0 0.0 
0.0 0.0] which guarantees that the base color of the medium will show 
through.  The only way to counter that would be to lay down a layer of 
chalky white ink, something like the liquid eraser used on impact 
typewriters, and overprint that with any desired non-white colors.  You 
would want to be pretty careful about how you handled a page you had 
treated that way.  There doesn't happen to be an opaque white in 
PANTONE, because it would probably be impractical to make a white ink 
thick and viscous enough to cover all underlying colors reliably.  That 
is not a failure in the process, it is simply a recognition of the 
facts.  So long as you are content to view your colored documents on a 
display, you can generate the effect of white light, but when you want 
to produce a copy on paper, you more or less have to start out with 
white if you want white, no matter what color process you choose.  Try 
printing on an ink-jet printer with green paper.  I don't see how even 
ICE is going to solve that.

Pierre