Before the invention of photography

The camera obscura or dark room has been a well-known concept since the Middle Ages. By sealing a room against all light, except for a small hole, you can project the inverted image of external objects onto a blank screen inside the room.

By placing a convex lens at the aperture and using a mirror to correct the image, it is possible to view a clear image the right way up. Painters made use of them to draw true to life.

The action of light and photosensitivity were observed very early on. Skin turns brown in the sun and it is said that a Mr. Bayard used a cover to mark his initials on the fruits of his orchard.

Alchemists discovered the properties of silver salts during the Renaissance. Silver chloride, a photosensitive substance, was then called "lune cornée" or "horn silver."

In around 1780, Professor J. AC. Charles drew a silhouette using light by treating paper with the substance.

Thanks again to photosensitive substances, in 1802 Thomas Wedgwood and Humphry Davy were able to trace the outlines of the images they created.
But these images were fleeting. As soon as they were exposed to light, they disappeared as the paper turned completely black.

Lithography was developed by the German Senefelder in around 1798. The practice made it possible to print images without engraving them. He discovered that limestone coated with a greasy substance, then moistened, only retains ink in the places greased by the artist.

In 1816, Nicéphore Niépce began his experiments in photography. He was therefore more than 51 years old when he first became interested in optical instruments and embarked on his research on photosensitive properties.
His goal was to produce an image, an image that was permanent, positive, and easy to duplicate.