[plug] OpenOffice.org in a pre-press environment.

[James Devenish]

In message <1105840941.3537.1.camel at latte.internal.itmaze.com.au>
on Sun, Jan 16, 2005 at 01:02:21PM +1100, Onno Benschop wrote:
> my logo was originally a GIF

Aiee! :) Please don't tell me you were using it at 72dpi, too :)
I assume you mean that you are now using something other than a GIF.
But what?

> The printer also complains that the text boxes are RGB, even though
> they're black, and even selecting CMYK/Black made no difference.

OpenOffice seems to encode its colours like this:

Black: 0 0 0 RG 0 0 0 rg 
Dark red: 0.501953 0 0 RG 0.501953 0 0 rg

In PDF terminology, I think these are "DeviceRGB" colours. The problems
are twofold. Firstly, those DeviceRGB values can't be used by a full-
colour CMYK print process because such a process does actually have any
red, green or blue inks. Thus, the colour must be transformed from RGB
to CMYK. Secondly, this produces a mirky and wasteful result because the
naive mathematical operation will give CMYK values of 1 1 1 0 (i.e. the
printer will consume cyan, magenta and yellow inks at full strength to
produce a dark mirky brown instead of using the pure black ink). The
general solution is to design a page in CMYK. Alternatively, it is
probably possible to go down the path of colour calibration in which
perceptual values are stored in the PDF and converted to best- guess
device values when the PDF in rendered on screen or in print (this is
what Mac OS X does). Better file a bug with the OOo team so that OOo
will output in CMYK instead of RGB. This won't give you "WYSIWYG"
results, nor will it give your the result you'd get by paying a graphic
designer, but it will make 'small office home office' production more
accessible.