http://petapixel.com/2015/03/05/a-look-at-how-colorizer-dana-keller-breathes-new-life-into-historical-photos/

https://www.tobiamontanari.com/memory-colors-an-essential-tool-for-colorists/

“Memory colors are colors that are universally associated with specific objects, elements or scenes in our environment. They are the colors that we expect to see in specific situations: these colors are based on our expectation of how certain objects should look based on our past experiences and memories.

For instance, we associate specific hues, saturation and brightness values with human skintones and a slight variation can significantly affect the way we perceive a scene.

Similarly, we expect blue skies to have a particular hue, green trees to be a specific shade and so on.

Memory colors live inside of our brains and we often impose them onto what we see. By considering them during the grading process, the resulting image will be more visually appealing and won’t distract the viewer from the intended message of the story. Even a slight deviation from memory colors in a movie can create a sense of discordance, ultimately detracting from the viewer’s experience.”