I would like to make some zone plates on a high contrast 35mm film. I used Kodalith years ago to make word slides, but am having trouble finding a replacement for this. I purchased some Arista Litho A/B developer and Rollei Ortho 25 film to try that out. I shot a test roll bracketing widely and after development (the recommended 3 min.) the film was completely clear. I shot another roll and really went crazy with long exposures. This time I got some highlights of an outdoor scene, very high contrast as I wanted, but the image was still way off, even greatly overexposed. Has anyone had success with any combination of film and developer for this purpose - a high contrast slide like the graphic arts Kodalith film did so well? I've searched the APUG site (and the internet) for this, but almost everything I have found relates to trying to extend the range of a high contrast film. I need a dense film with truly high contrast. Thanks for any help.