Though actresses have to worry about the incredibly high quality of HD film picking up their every imperfection these days, the ladies of film had an entirely different problem in the 1920s. Because of the price, Orthochromatic film stock was the standard during the birth of film but was rather insensitive to red and yellow light on the spectrum. The processes used to correct this insensitivity to red and yellow in post-production would make it oversensitive to blue and violet. Make-up wise, this means that actors and actresses had to be made up with highly exaggerated and contradictory colors in order to look natural on film. Hence the hooker face.