How to make pinhole camera obscura and glowing erasable picture
The percussion chamber, also called camera obscura, is a simple device made of an opaque container with a small hole. Through the opening the light enters and on the opposite side of the chamber the projection creates a inverted image of the scanned scene. If we place a light-sensitive film in such a chamber, the image remains captured on the photographer.
I used a phosphorescent color as a light-sensitive substance. The parts that were illuminated will remain bright, and the parts that have not been illuminated will remain dark. The disadvantage is that the image is weak in time, on the contrary the advantage is that a new photograph can be created over and over again.
Put the phosphorescent paint on a wooden plate and let it dry.
Put a small circular hole on the side of the paper box with an approximate size of 15x25x10 cm.
To improve the optical properties, cover the hole with a small magnifier that acts as a lens of the camera.
From the top of the box, cut a large rectangle.
On a polystyrene prism, use a double-sided tape to apply the light-sensitive layer that we have prepared at the beginning.
Moving the wooden insert focuses the image on the subject.
Cover the top hole with a piece of cardboard so that the light does not penetrate into the box and let it take a picture for at least 2 minutes.
Put the box into a dark room and choose a wooden board. A scanned scene photograph will remain on it. The image becomes weaker for a few minutes until it disappears. However, we can still use the plate and experiment with image recording.
On the light-sensitive layer, the shapes of various objects can also be recorded after lighting. Uniform illumination will erase the image.
Video from production and testing of the pinhole chamber.