I'm not sure how clear the content project will be for the average viewer.
I agree with that. Might I propose that one solution to that problem would be to set up the background with appropriate apparatus and utensils so that the scene looks like a lab with some beakers, measures or bottles of chemicals. Even if the viewer doesn't understand that he is looking into a photo lab, he will understand that it is something "scientific."
Alternately, place a labeled bottle somewhere in the picture such that the viewer can see the word "Kodak" or "Ilford," etc.