To clarify, my intent is to create an inverse-video of a black-and-white (or, more generally, a grayscale) figure. It would be nice to be able to do this easily with Inkscape and ultimately from the command line for a grayscale PDF. Incidentally, the source of the four figures assembled here was mat...

Hello. When I select all and then use Filter - Color- Invert (possibly after drawing a white rectangle behind everything, or before using Document Properties to set the bg to black) on the attached file, the borders of the four plots do not get treated: they are left black and therefore become invis...