We had a VERY interesting demo session from Randy LeSage last night and I know that I am going to try this technique! The photos below are somewhat of a photo essay/documentary with Randy as he actually producing prints and collages.
These are useful links to the materials that Randy used
Gelli Art Printing plates https://www.gelliarts.com/collections/gel-printing-plates
Akua Colors https://www.akuainks.com/