There aren't support for Pantone color in Inkscape, because, amongst other things, there is potential legal issues with Pantone, as discussed here. As some printer (read: adobe preacher) asked me to use pantone colors in my pdf, I was screwed and had to pull some old Illustrator version kicking around. To my surprise, a 32k file from inkscape turns into a 96k file from Illustrator, eg: its apple and oranges. There are object types, such as colors, that allow to name colors ; the Pantones are defined as objects, and are used as arguments. Not only Illustrator uses \r\n instead of just \n, rendering diff messy, it completely restructure the file. There are already swatches of pantone colors available via the internet, but they don't have the "names", hence, can't be used by a printer.