CMYK overprint
Wonderful Inkscape unfortunately does not support black overprinting. You can define colors in CMYK but it will not allow values such as 40% C + 40% M + 40% Y + 100% K (Inkscape for some reason automatically converts these back to 0% C + 0% M + 0% Y + 100% K).
Left: cyan plate after importing .svg in Scribus.
Right: cyan plate after adjusting colors.
But with the help of excellent Scribus, this is easy to fix. Simply import the .svg into Scribus, and go to edit > colors. All colors in imported Inkscape illustrations, will be RGB; most likely black has ended up as ‘FromSVG#000000’, or ‘Grey0’. Change this color from RGB to CMYK and change values to 40% C + 40% M + 40% Y + 100% K. Check in print preview and … voilà!
4 Comments ↓
1. taiabati
Jun 29, 2007 at 9:08 am
The trick is nice and easy for the black overprinting thing, but it gets you to convert to CMYK (again) all the remaining RGB colors in the graphic, not just the black one. So it could end up in a “color re-conversion madness” in case the design is complicated with many objects and different colors… Or did I get it wrong?
By the way. I love this blog.
2. Femke
Jun 29, 2007 at 10:57 am
Hello!
I tested (not on a proper proof, so no guarantees) the way Scribus converts RGB to CMYK, and it seems to make no difference whether you manually select CMYK-per-color, or ask Scribus to convert the whole document. But… there is still an issue of course with colors & shades that have lots of black in them, so you are right: color-converting-madness is far from over.
Soon we will do a proper report on SK1, a tool specifically developed to help with these kinds of problems. http://sk1.sourceforge.net/
3. tomh
Jul 17, 2007 at 1:05 pm
Inkscape doesn’t support CMYK because SVG doesn’t, or at least the base of SVG colours are sRGB unless using specific colour profiles (which can’t be set yet in inkscape…)
4. Graduado Social Sevilla
Oct 9, 2010 at 1:23 pm
all the remaining RGB colors in the graphic, not just the black one. So it could end up in a “color re-conversion madness” in case the design is complicated with many objects and different colors… Or did I get it wrong?