[Scribus] CMYK or Sending to a Printer

[Dennis Noordsij]

Hi List,

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 
the same.

- 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 
blueish tint.

- 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 
use.

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 
output format.

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 :)

Any tips?
Cheers,
Dennis