From ColourWiki

Informations about colour management in Scribus

Mixed Colour space documents in Scribus

Other than suggested in Flat color vs. mixed mode documents Scribus (1.3.x) uses internally a mixed colour space model, thus allowing a late binding for maximum quality preservation. In detail; all incoming images are preserved by numbers. No conversion occure. The embedded profile is attached to the image object and a suitable is selected if no embedded was found. Goal is to avoid unnecessary CMYK->RGB->CMYK conversions.

An other policy in Scribus is observable during saving Scribus document as a final PDF.

PDF Target:

convert to sRGB
convert to print colour space, selectable in the Scribus colourmanagement preferences
keep numbers dont convert anything (only RGB or as well mixed RGB and Cmyk?)

profile download and installation in Scribus:

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