It’s not often that I post links here but this is a good one, an essential one. The guys at International Colorist Academy did an amazing job at building a timeline with all the major milestones in the History of colour correction and grading. It goes from the first photograph shot in 1826 to the first digital camera and the evolution of the telecine.
I strongly suggest anyone involved in color grading, online editing and image processing to give it a look. Here is the link: http://icolorist.com/library/history-of-color-correction/