In 1990-91, I made several color photograms while a student in grad school. They were made while I was taking a color photography class (in the class, we worked to improve our ability to see in color, and we also worked to improve our color darkroom printing skills).
We had access to Cibachrome printers. Cibachrome (also called Ilfochrome) is a now-defunct color process (if it’s not entirely defunct, it must be close to it). It was used to make direct positive prints from color slides. The process worked nicely for making photograms, as well, I think.
Here is a brief definition of photograms. Typically, they’re made in black and white (although they were sometimes made with the blue-toned Cyanotype process, too), so color examples are somewhat unusual:
A photographic print that is made by placing objects on light sensitive paper and then exposing the paper to light. The objects placed on the photo paper will selectively block light from reaching the paper, with the result that they will record all sorts of diverse shapes and shadows on the paper.
Needless to say, photograms can only be made with traditional photographic processes — A digital photogram is pretty much a contradiction-in-terms, although there are probably ways to simulate the look of a photogram in the digital medium.
If anyone from the Ilford Photo Company happens to be reading this, by any chance, and would like to offer me resources to begin making color photograms again, I’d be delighted to hear from you.