I just wanted to pop in a say that early black and white films could also be colorized by hand. This required separate treatment of each element within a frame.
In other words, if you wanted to have a character with a red dress and blonde hair, the dress would need to be painted red and the hair would need to be painted blonde in every frame showing that character. Because of this, many early films were only selectively colored (this was common in Edison's early films). As you may have guessed, even in the selectively colored films, this process was very painstaking and expensive. In fact, it could double the price of a film (Yumibe pg. 42).
Another interesting fact is that many colorists were women or young girls. A positive aspect of this was that coloring was one of the earliest ways that women could be involved in film production. The downside was that these female laborers were hired because they could be paid less than their male counterparts (Yumibe pg. 46).
One of the most notable female colorists was Elisabeth Thullier, who worked for Georges Melies. I wanted to bring up these two because of the film "A Trip to the Moon," one of the must-sees of the silent era, was directed by Melies and colored by Thullier and her team. The color version was thought lost until a copy was discovered in the early nineties. A restored color version of the film was shown at Cannes in 2011. You can watch it on Youtube here: https://www.youtube.com/watch?v=lUAD4lKNDI8
Sources:
Yumibe, Joshua. Moving Color: Early Film, Mass Culture and Modernism. Piscataway, NJ: Rutgers University Press, 2012.
Mintzer, Jordan. "Restored 'Trip to the Moon' Debuts on Cannes Opening Night." The Hollywood Reporter. Published 5/10/2011. Accessed 5/31/2016. Available at: http://www.hollywoodreporter.com/news/restored-trip-moon-debuts-cannes-187115.
Notes: I am an amateur, not a historian. Also, if my reference to the 2011 Cannes screening breaks the 20 year rule, I'd be happy to remove it. I included it because most of the information I could find about re-discovering the colored film and the restoration process was in 2011 articles like the one I cited.
Hand tinting was extremely common, all the way through the mid-20th century. My baby pictures from 1959 were done that way, and hobbyists still practice the art.
It was, of course, most common for prints on paper, because you didn't have to color such tiny, tiny areas. Special long-lasting dyes were most commonly used, along with tiny paintbrushes. Less common, but not unknown, was the practice of hand-tinting transparencies that could be projected via magic lanterns. Here, for instance, is a hand-tinted view of a county park that was used circa 1915 to promote the (Burnham & Bennett) Plan of Chicago. Similarly, this aerial view. Or this breathtaking aerial of Chicago's Uptown neighborhood.
There was man who lived in Russia during the reign of the Tsar (we're talking the turn of the 20th century, circa 1900) named Sergey Prokudin-Gorsky. A chemist and photographer, he experimented with different methods of producing color photography-- the one method which produced color photographs involved taking three different stills (with a camera that shot in black and white, if I'm not misraken) of the same shot in red, green, and blue filters. Afterwards, the images were composite into a work that seems almost modern in its coloration. You can Google his name for some of his works, as they truly are fascinating.
Sources: Photographer to the Tsar: Sergei Mikhailovich Prokudin-Gorskii. Library of Congress.
Garanina, Svetlana (2003). "Sergei Mikhailovich Prokudin-Gorsky Biography"
Adamson, Jeremy; Zinkham, Helena (2002). "The Prokudin-Gorskii Legacy: Color Photographs of the Russian Empire, 1905-1915"
