Once upon a time, I had a 600 dpi Apple laserwriter printer, and it occurred to me that scalable graphics were suboptimal. I wanted to directly access and control every dot at full resolution without letting something else rasterize for me. I eventually figured out how to print my fractals and magnetic field diagrams that way, although I've forgotten the details now. Seems like this would be a good way to do graph paper - make sure you were printing lines exactly one pixel wide.