Object's color changes when exporting to PDF

[tforjan]

Hello forum members,

a strange thing occured to me. Maybe it's strange to me only, so I thought I'd ping you about it.
I imported a vector image, assigned some colour to it. Then created a PDF, opened it in Inkscape, and realized that the object has different color than what I assigned it in Scribus.

This is how I did it:
- created an SVG graphics file in Inkscape
- imported it into Scribus 1.5.5 using Get Vector File
- Used the Colorize function to assign a predefined color to it (CMYK 100;0;15;34)
- Created a PDF which I opened in Inkscape and verified the object's colour

At first I thought this may be a Color Management side effect, so I tried both with and without Color Management enabled. The very same thing happened both times: the object's color in Inkscape seems to be CMYK 100;22;0;40 instead of the one above.
Any idea what's going on and how to make sure my PDF output has the right colour?

[a.l.e]

can you please share:
- an svg created with inkscape
- a .sla with the imported svg and the new color
- the created pdf

you can simply put a rectangle with the right color in the svg...

it's likely that you discover what you issue is, while creating the demo files.
and if it does not happen, then we will have some files to play around and reproduce your problem.

ciao
a.l.e

[RodneyLee]

is it possible the .pdf is outputting RGB and not CMYK?

[tforjan]

is it possible the .pdf is outputting RGB and not CMYK?

To me it looks to be CMYK. Scribus knows its thing.

Attached a set of files - the SVG, the SLA and the product PDF. The imported rectangle is painted to "Teal Green" within Scribus, not using the object's original color.

Honestly, I was hoping this was some typical user error.
Do you see anything suspicious?
Thanks for bothering.

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[a.l.e]

here is how i see your rectangle in the pdf in inkscape:



in the front you see the color dialog from scribus, with the color from the .sla:

- the colors seam to visually match
- when i look at the values, without doing the maths, the M and Y channels seem to be switched between inkscape and scribus.
- scribus shows the same color when opening the .sla and the .pdf

i'm trying with one of the inkscape 1.0 betas / alphas...

checking the same things on your computer might help you find a path to a solution...

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[tforjan]

I got the very same results here.
Could be an Inkscape error, but I have no other tool to analyze a PDF. Yet, the CMYK values in Scribus and Inkscape actually differ, not just "mixed up"...

[a.l.e]

i would suggest not to check the colors with inkscape.

it's a rgb tool, that only got very recently (limited) cmyk support.

i would say: if you don't have professional tools to check the pdf, just trust scribus...