Q: How do I display an image at a particular size (in mm)? I'm trying to use my iPhone as a light source and a digital negative to make analog prints.
For example, the Paper Exposer app generates a light source that when placed behind a 35mm strip of film and a camera, works as an enlarger).
The difficult part is getting a photo to appear at 35mm negative size (22mm by 16mm) so it won't be cropped by the film camera's shutter.
