When I first began shooting Zoneplate images, I instantly became interested in creating my own Zoneplates with a number of zones and to accommodate a variety of focal lengths. The traditional process of creating Zoneplates, is more work that it needs to be especially if you are concerned w/ the accuracy of your final Zoneplate. Accuracy is also a concern for Pinhole photographers when creating their self-made apertures. You can also use this same process to create pinholes.
Having a background in Graphic arts and the processes involved to create plates (not to be confused w/ Zoneplates) for offset printing presses. I've had plenty of experience in the days before Direct-to-plate technology using a output device called an imagesetter. When creating plates for offset presses accuracy is a must and at the time the imagesetter heeded that call. The imagesetter is still used at many local print shops for both Screen printing and Offset printing.
If you don't know what an imagesetter is check out http://en.wikipedia.org/wiki/Imagesetter.
I'll upload the instructional photos asap, in the meantime, I have all these steps w/ photos here.