yOu could go as far as using a clear polyester material with transparent dyes smeared on that can cause all kinds of funky results as well.
print deep and let the dyes act as a doging tool.
We use to swing optical glass under the lens and put all sorts of material in the light path to create effects.

Only trial and error will help you here, don't kill me if it dosen't work , I am only the messanger.