Juice Box Pinhole Camera

Step 3 Adding the Back

The next big step we need to take is to add the back on the camera.
The back will cover the larger hole on the box, but we need to need to tape it correctly in order to get it to work right. The film will feed from the right side of the box, between the back we're going to make and the larger hole, and out again.

So, to start, we know that the width of the film is 35 mm, and for room's sake, we'll round that up to, say, 38 mm. And we also know the width of the Yoo-Hoo box is 4.5 cm (45 mm), so we should take our cereal/beer box cardboard and make (in our case- your box may be different) a 35 mm by 45 mm square.

Once we have our square, whip out the electrical tape, and tape around the edges of the cardboard square. Then, tape the cardboard square down on the back of the juice box.
However, DO NOT tape the left and right sides of the camera. Remember, the film's feeding from left to right between the square and the box.

Note: Use tape liberally. Very liberally. Any light that gets through can ruin the whole thing, and since black electrical tape is non-translucent, it's a surefire way to keep it light-tight. When in doubt, tape more.