[softwarelist] Re: colour corrections

On 30/11/06 1:06 pm, "Martin Wuerthner" <public@xxxxxxxxxxxxxxx> wrote:

> In message <e54be88d4e.arnold@arnold.>
>         Arnold van der Heijden <info@xxxxxxxxx> wrote:
> 
>> When I use -for example- 100% magenta in Ovation, print this
>> postcript, the file never gives, depending on the jobobtion in
>> Distiller, 100% magenta in pdf.
> 
> This is not surprising. The RISC OS printer driver is strictly
> RGB-only, so what ends up in the PostScript file is always an RGB
> colour. This is not OP's fault - there simply is no way to tell the
> printer driver that a CMYK colour is desired. So, in the case of the
> standard 100% Magenta CMYK colour definition, the colour setting in
> the PostScript file reads:
> 255 0 255 C
> which sets 100% Red, 0% Green, 100% Blue, which is the naive
> conversion of 100% Magenta from CMYK to RGB. It is highly unlikely
> that any printing pipeline will render that as plain 100% Magenta.
> 
> By the way: It would be almost trivial to enhance the PostScript
> printer driver to allow applications to set CMYK colours. This will
> probably be done as part of the PostScript 3 driver project. Adding
> support for that to OvationPro should be very easy.
> 
> As a further aside: OvationPro does have special code to bypass the
> printer driver in order to print CMYK bitmaps to PostScript correctly.
> This has a long tradition: Impression did it already, and ArtWorks
> does it (I added that for ArtWorks 2.4).
> 
>> I tried all kind of settings, different joboptions, colour
>> correction turned on or off. But I can't get 100% magenta
>> as 100% magenta in pdf. It does not matter Ovation Risc Os or
>> for Windows.
> 
> The only way to get CMYK colour definitions for shapes and text into a
> PDF file under RISC OS is to use a program that generates PDF files
> directly instead of going through the PostScript printer driver, which
> flattens everything to RGB. If you export as PDF from ArtWorks 2 you
> get all your original CMYK colours in the PDF file.
> 
> Martin

As an aside to my previous reply, I recently read that a major magazine
publisher has now adopted an RGB workflow so maybe RISC OS is just ahead of
the game.

Mike Williams

Other related posts: