Answer: Shirley Card

Although photo development technology advanced significantly over the course of the 20th century, no amount of automation every proved to be a perfect replacement for the human eye and the viewer’s acknowledgement that a photo looked balanced and pleasing.

In the 1950s when the Kodak film monopoly was broken up and independent photo labs sprung up across the U.S., Kodak came up with a novel way to help all these independent labs calibrate their equipment properly: Shirley cards. The cards were actually photo negatives that were developed on the local lab equipment to test color density, tone, and contrast. The original Kodak model was named Shirley and the name stuck: for the ensuing decades the test negatives and the resulting 4×6 photos were known was “Shirley cards” regardless of whether or not Shirley appeared on them.

Although the development process is largely entirely digital at this point (and most photographers no longer even use film), Shirley (and her photographic descendants) can still be found in photo lab calibration software today.