[Scribus] CMYK or Sending to a Printer
Tue Nov 2 23:52:06 CET 2004
Having made an ad in Scribus to be printed in a local magazine, I am a bit
confused about some aspects of preparing a PDF to send to a printer.
That is apart from the "your PDF is malformed" which turned out to be "we
can't handle embedded TTF, only Type1" :)
My confusion is with the CMYK model. Of course in the precious little
information they give they simply insist everything has to be in CMYK. No
more info, no output profiles, PDF versions, anything about the printing
process, just "no RGB!".
I have tried the following with and without color profiles, results are mostly
- Use an RGB PNG in Scribus, export as PDF to Printer (no CMS), which
according to "identify -verbose mypdf.pdf" outputs a CMYK PDF. The problem
is, the image is really flat (same with CMS actually). I thought well it's
still OK, so sent that. They (printers) said they could not fix the image
because brightening it only throws away more of what color is left.
- Use ImageMagick to convert the PNG to a CMYK jpeg (and use in Scribus,
export to PDF for Printer). Firstly this gives a blue-inverted jpeg I seem to
remember from the CMS docs. Resulting PDF is still not cool, has the same
- Use ImageMagick to convert the PNG to a CMYK tif file (and use in Scribus,
export to PDF for Printer). This gives an entirely different, much darker,
slightly better, but still not acceptable result.
Export to RGB PDF gives a perfect picture obviously. Somehow the red text and
logo manage to show up perfectly red in all PDF's, screen and printer, under
all circumstances, (and they printed to the same perfect red), but then they
manage to show up in brown if I enable CMS (even though they print to red).
The red logo surviving is intriguing because if I gimp together a full
spectrum image (i.e. rainbow gradient left-to-right) and use that in the ad,
very few of the colors survive the CMYK export, even with CMS for my monitor
(supplied by manuf.) and .. random printer? I don't know what printer they
I know the conversion is supposed to affect the colors a bit, but I have here
4 different results (more if CMS variations are included) depending on input,
and even 2 different CMYK conversions of the same PNG depending on JPG or TIF
Basically - what I thought I'd do is output the result to a CMYK PDF where the
CMYK is simply the mathematical conversion from RGB, without any profiles or
gamut considerations or throwing away information. I'd then trust the
printer's system to make a reasonable -not perfect- print of it. But the PDF
itself already looks bad -before they even look at it- so I must be doing
something wrong somewhere :)
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