--- Gelatine, jello, and some gum are basically the same thing, just differ in strength and purity. They came from animal bone and / or skin. Have you notice that when you make chicken stock by cooking chicken neck bone for a long time, the stock is kind of thick and form jell like jello after it is cold.---Time for me to chime in... I have discovered that all manner of gelatine can be used to make passable (if you are not too particular) gelatine prints. Animal proteins (apologies to the vegetarians among us), vegetable proteins, and even some starches seem to work.
My most impressive result was a clam-chowder print. In chemical terms it is a nice mix of all of the above.
Dan Shapiro