My current work around is to do just that or in most cases I change
colourspace of the pdf (including and especially images) using
moonshiner. It doesn't always not retain CMYK colour values for vector
objects, it is an extra step I would like to avoid. I was wondering if
anyone else has been successful in using Ghostscript to convert the
colourspace of a PDF, but integrated into the export dialogue maybe as
plugin. Its a slight hassle to import an SVG file, update the CMYK
on each object,export to PDF, send the file to my local printer, do a
proof print with them, change the colour again in Scribus, export to
PDF. I guess I will just have to continue along this way of doing
things, until I have figured out how to what I want myself :)
You have to attach a CMYK color profile to your inkscape document in the
document properties. Once you have the profile, the CMS tab in the
fill/stroke dialog allows you to choose the colorspace for each object
and select your desired CMYK values.
If you do that and take the SVG file to Scribus, the CMYK values will be
Regarding the spot inks, as far as I can remember you can use the auto
palette for adding swatches that work "globally" in the document, but
since that's done by custom gradient definitios they don't survive the
import to Scribus as spot inks.
It's not really a problem, since the color of a spot ink is meaningless.
The color of spot inks is just a visual aid for you to pick them, but
the printer will produce a separate plate for them that has to be inked
with the right color.
So, don't worry about spots in inkscape then. Just use a regular RGB
color and when you import the SVG to Scribus, go to the colors manager
and turn that RGB swatch to a spot ink, using the name of the desired
ink so it's reflected in the PDF output. The printer will know what to
do with it.
I run a small graphic design firm, and I send files to printshops almost
daily. Personally, I don't even care about doing anything in CMYK in
Inkscape. I do everything in RGB, and let Scribus to create the
Spot-only works are the exception, of course. But since printing 3 spots
is usually as expensive as printing process, most of the jobs end up
being just process, with a few exceptions.
CMYK+Spots is not very common as one would expect, but it's not a
problem if you use the intermediate binding process I just described.
You do everything in RGB, and if something has to be printed in a
special ink, you can mark the RGB swatch as spot in Scribus and it will
take care of it.
In my experience, properly color managed RGB > CMYK conversions are
pretty reliable. Designers usually think that a special CMYK combination
is a bullet-proof method to get exact colors, but that's not true: a
certain CMYK combination is tied to a specific press setting (plate
order, screen angle, stock type and quality, etc.)