Autochrome was an early color photography process introduced in 1907 by the Lumière brothers. It used a glass plate coated with tiny grains of potato starch dyed in three primary colors: red, green, and blue. When exposed to light, these grains created a color image by filtering the light that passed through them. The process was popular until the 1930s, as it allowed photographers to capture vibrant colors in their images. However, it had limitations, such as long exposure times and a lack of sharpness. Eventually, it was replaced by more advanced color film technologies, leading to the modern color photography we use today.