Eli5: How do photo restoration artists know the supposed colors of greyscale images?

Question

Are the colors based purely on their assumptions/imagination, or do the greyscale images retain some sort of data that tells what color on what part?

In: 641

Answer 1

Different shades of grey align with different colors. So a really dark shade would likely be a dark blue/red/purple. Then it comes down to knowing the fashion trends and what colors were used at the time,in that region, and the economic class of the person. They can also consult written accounts for colors of things like military uniforms.