Troy Henderson said:

I tested this on a black-on-transparent EPS that was created via MetaPost, and it seems to work fine. If you are not using Linux (or Unix or Mac OS X), let me know and I can probably >put together a quick HTML page to do this on my server. Thanks for the invitation. Fortunatly I’m using GNU/Linux.

...

cat foo.eps | sed -e "s/0 0 0 setrgbcolor/1 1 1 setrgbcolor/g" > bar.eps

It simply translates the (0,0,0) triplet (which is black) to the (1,1,1) triplet (which is white). This is very simplistic and may not do all that you want.

Unfortunatly there is no such a sequence in my file: grep setrgbcolor a1.EPS /setcmykcolor{1 sub 4 1 roll 3{3 index add neg dup 0 lt{pop 0}if 3 1 roll}repeat setrgbcolor pop}wd /sw/setlinewidth ld/scap/setlinecap ld/sj/setlinejoin ld/sm/setmiterlimit ld/sd/setdash ld/rgb/setrgbcolor ld/crgb/currentrgbcolor ld/cmyk/setcmykcolor ld/gs/gsave ld/gr/grestore ld But thank you for gave a try.