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

>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?

More of the former and less of the latter.