I recently printed some photos with my old Canon Selphy CP720 and because I ran out of paper I started playing with the empty cartrigde. What I found, you can see in the next photos.
This is the empty cartrigde As you can see this is what we can find inside the used cartridge. Ok, there is no wow until I do this. I ”scan” the film with my camea like in the image bellow… Then I inverted in Photoshop… Original image Image inverted Turned into grayscale, and auto-adjusted for contrast: