ehm ehm...
i had a look at the way the barcode creator works and i came to the conclusion, that it's not correctly implemented.
it should not provide you with an open choice of rgb colors, but just let you choose among colors that are already defined for the document.
no reason to allow other colors, here.
(most of the time you will want transparent / white and black anyway)
i will open a ticket for it.
now, i see two workarounds for you:
- you work in RGB and use the correct ICC color profile to get scribus to convert the colors to CMYK while exporting to pdf
- after having created the barcode, ungroup it, select all the vertical bars (not the background, not the numbers below) and set their background color to a CMYK color (probably black), select the numbers below the bars and set their fill to the CMYK color, select the background and delete it or use the right color for it.
(the best way to select the different type of items is to drag select from outside the barcode... easier to show and do, rather than explain...)
have fun
a.l.e