On Jan 14, 2020, at 8:42 AM, Bob-BTY via colorsync-users <colorsync-users@lists.apple.com> wrote: I wonder how old the 'Standard Observer' was?
Multiple ages! There is no single person used to produce the model we know of as the Standard Observer: Establishing Standard Observers In 1927, physicists John Guild and David Wright gathered subjects and performed a color matching experiment to determine how the average person perceives color. Subjects were asked to look through a hole and match each color in the spectrum by combining various intensities of red, green, and blue lights. The hole only allowed a 2 degree field of view (similar to looking at one's thumbnail from arm's length distance or equivalent to a 1.7cm circle from a 50cm distance) because of the belief that our color-sensing cones were located in a 2 degree arc in the fovea, a region of the retina. Note as well, the In 1964, the CIE defined an additional standard observer, this time based upon a 10 field of view; this is referred to as the 10 Supplementary Standard Observer. According to this site (verification necessary) https://medium.com/hipster-color-science/a-beginners-guide-to-colorimetry-40... <https://medium.com/hipster-color-science/a-beginners-guide-to-colorimetry-401f1830b65a> “In the 1920s two color scientists, W. D. Wright and J. Guild, each performed similar color vision experiments. Wright performed his experiment on 10 subjects, Guild used 7. Their results agreed with each other so well that they were combined by CIE to create the RGB color matching functions we’ve been discussing.” So if we inspect the actual history, we see that the Standard Observer is an ‘average’ of many samples just like D50 is a sample of many actual cases of data collection. Andrew Rodney http://www.digitaldog.net/ <http://www.digitaldog.net/>