I'm kinda angry, cause I messed up 150 A3 color laser prints, 'cause inkscape does not give you the option of not using transparency while exporting. Point is, I made a plakat for a party at my university and when converting a png with transparency to cmyk, the transparency is lost and it's the color as solid. Since I only made the png and was not there when printing I didn't notice that I forgot to put a white rectangle in the background. You see, I actually had encountered about the problem before, but had just forgotten to draw that rect, cause you don't notice the difference in inkscape and don't always think about that kinda crap. It cannot be that hard to make a check box in the export dialog, that allows you to reduce the image without transparency. Gonna file a bug on this. Hope it'll be in 0.38.
David