RE: CMYK printing

[David Williams <DavidW@xxxxxxxx>]

Thomas Callan 3337 Analyst_Programmer (thomas@ref.collins.co.uk) wrote:
> I have been having some issues with printing to Postscript files using
> CMYK colours.  Some colours defined as CMYK seem to be OK, but others
> convert to RGB.  The only difference I could find was that the colours
> that printed OK were defined as Print as Process and the colours that
> converted to RGB were defined as Print As Spot.  I just wanted to check
> if this could be the reason for the conversion to RGB or if there could
> be anything else....
> 
> (Using Frame 6 on a unix system)

You have probably identified the cause correctly. 

Here's an explanation of the basics, and a warning of where
you might see spot colors used even when the only colors
in use are cyan, magenta, yellow, and black.

-

"Print As Spot" effectively means add a color (of the
exact name defined) to the output. In traditional (press)
printing, this means adding a separation for that color
and the result is another film negative and/or printing plate 
and a pass on the press with that color of ink. It adds 
to the cost of printing, so it is a bad thing to do
unintentionally.

Some prepress systems can compensate for this error and 
return CMYK (or other color system) values for the spot
colors. Even so, it is better to avoid unintentional spot
colors.

-

A spot color is something with a color name not in
the process colors (usually CMYK).

It is even possible to get, for example, Black printing
as a spot color in addition to CMYK, because it has been 
named something different than the process color black (K). 
Even if you avoid this in FM, you may see this effect in graphics 
imported into FM after being created in something like 
Illustrator or Freehand. It is a common error especially
among novice or non-s[pecialist designers.

-

Regards,
David
-- 
David Williams. Writing personally. Working in Cambridge UK.

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