DIY Pinhole Camera from a Tin Can

Before lenses were invented, camera obscuras used nothing more than a tiny hole in a dark box to project an image onto a surface. This pinhole camera uses the same principle. Light rays from a scene pass through the pinhole and diverge onto photographic paper — producing a real, inverted image. Developing the paper reveals a negative image of whatever you photographed.

What You’ll Need

• Empty cylindrical tin can with lid (e.g. coffee or cocoa tin)
• Black spray paint or matte black paper for interior lining
• A sheet of RC photographic paper (buy from a photography store or online)
• Thin aluminium foil (from a drinks can)
• A sharp pin or fine needle
• Black electrical tape
• Darkroom chemicals (developer, stop bath, fixer) OR access to a darkroom
• Red safelight (for loading paper)

Step-by-Step Instructions

1. Prepare the can: Paint or line the interior of the can matte black to prevent internal reflections.
2. Make the pinhole: Cut a 1 cm square of aluminium foil from a drinks can. Using a pin, pierce a single hole in the centre — rotate the pin gently for a clean, round aperture. Smaller = sharper image (but longer exposure needed).
3. Mount the pinhole: Cut a 1.5 cm hole in the exact centre of the can’s base. Tape the foil square over the hole, pinhole centred, with black electrical tape. Seal all edges.
4. Load the paper: In complete darkness (or under a red safelight), cut photographic paper to fit the can’s interior curved wall. Slide it in with the emulsion (shiny) side facing the pinhole. Replace the lid and seal with tape.
5. Expose: Aim the pinhole at a bright outdoor scene. Cover the pinhole with a small piece of tape as a shutter. Remove tape to expose for 2–30 seconds depending on light conditions.
6. Develop: In the darkroom, slide the paper into developer for 90 seconds, stop bath for 30 seconds, fixer for 2 minutes. Rinse thoroughly and dry to reveal your negative image.

Safety Notes

• Darkroom chemicals are irritants — wear gloves and work in a ventilated space. Never mix developer and fixer.
• Keep photographic paper away from all white light before and during exposure — even a brief flash ruins it.

Tips & Troubleshooting

• A blurry image means the pinhole is too large — remake it with a finer pin.
• A very dark image means overexposure — reduce exposure time next attempt.
• Scan the negative and invert the image digitally in any photo app to see the positive image.