George Eastman was the first to produce 35mm film. Beginning in 1880, he designed a paper coated with gelatin. Hannibal Goodwin modified the process to create nitrocellulose film, while Emile Reynaud added perforations to make it go through the camera easier.
Each frame of 35mm film is made up of millions of light-sensitive compounds. These compounds are comprised of silver and halogen. As the film is struck by light, the silver ions create a latent image. Development of the film brings this image to full visibility.
While the process to make colored film dated to the early 1900s, it wasn't until Kodak released stock in 1950 that films began to utilize the concept fully. Before this time, a series of prisms in front of black and white 35mm stock were used to create the illusion of color.
A number of different formats for 35mm have been created over the years. These involve different aspect ratios, which in turn determine the size of the projected image in a theater. Examples of this include widescreen and VistaVision.
Originally the perforations in 35mm were rounded. However, it was found during the early days of motion picture production that these holes were subject to increased wear. In 1908, Bell and Howell created a new type of perforation that was square.