PrintaRonchi is a small Windows program for drawing Ronchi screens. It works only in pixels (dots on a printer). More than likely, your printer is not capable of drawing at the resolution required. Blowing up the image up by say x10 and then photo-reducing is probably needed.
Get PrintaRonchi.exe zipped.
Asuming you have it, note that the default line widths are 2 black pixels and 4 white pixels with a width and height of 600 pixels. On a 600 dpi printer this will give you 100 lpi on a one inch square. Try printing it and look at the result with a 1" eyepiece turned in the wrong direction. To blow it up by a factor of ten, change the above numbers to 20, 40, 6000.
Tom Stokes - Feb '11