Instant film is generally not the practical choice for homemade pinhole cameras. It’s difficult to use because instant systems rely on precise film handling and rollers to spread developer, so adapting them to a simple student-built pinhole camera is usually more trouble than it’s worth.

A better approach is black-and-white materials with a simple darkroom workflow. Two workable options mentioned are:

• Photo paper, including Ilford Direct Positive paper if you want a direct positive image rather than a negative.
• Black-and-white film, developed in a daylight tank after loading it in a changing bag.

For a class project, photo paper is often the most visual and educational option: students can watch the image appear in trays of developer, stop bath, and fixer, then wash the print. You’ll still need a basic darkroom or light-safe setup.

If your school already has darkroom access, that’s likely the easiest and most rewarding route. If not, a makeshift darkroom plus black-and-white paper or film is still more realistic than trying to use instant film.