Posts: 451
Threads: 107
Joined: Nov 2005
Got a lot of time?
Got a heap of plotter pens?
Got paper that won't fall apart when it gets soaked with ink?
It's possible, but I'd hardly recomend it. It required drawing lots of dots and that's what kills the fibre tipped pens the fastest. If you try to do it with the roller ball pens (which withstand the dot trick much better) you'll find that unless the dots are changed to be short lines, the ball won't rotate, and no ink will find the page.
Apart from all that, the inks don't mix too well (actually the mix very well, and you can easily contaminate a light coloured (fibre tip) pen by trying to plot too much over a freshly filled area of another colour). Another problem with overprinting (if you use CMYK colours) is that they tend to bleed.