Photographic technology evolved significantly from the late 1800s to the 2000s. Early photography relied on wet plate and collodion processes, which were time-consuming. The development of flash powder and halftone printing in the early 1900s increased the speed of photography. The golden age of photojournalism from the 1930s-1950s was enabled by the compact 35mm Leica camera and development of light bulbs. Digital cameras replaced film by the late 1990s and 2000s, changing the process of photojournalism.