Common Polaroid camera in paintng

I have three or four of these cameras. I bought them the first time I taught Film 311 and we used them for an in-class demo on image transferring. Percy Fuentes was in the class and he eventually cracked the secret for how to do it (after about an hour of us all trying). It had to do with wetness of paper to be transferred onto, pressure with the roller, and timing. The next time I taught the course, the film was no longer available (the pull-apart polaroid) so I never used these cameras again.