From Technology Review: Enhancements to image-processing technologies for colorizing black-and-white images are helping curators divine the colors used by the French artist Henri Matisse on his landmark work Bathers by a River–while the painting was still a work in progress.
The tricks deployed by curators could be more widely relevant to other colorizing applications where it’s not obvious what the colors should be in a black-and-white image of a piece of art, or in cases where subtle differences are important and should be highlighted, such as in medical images.
Researchers at Northwestern University used information about Matisse’s prior works, as well as color information from test samples of the work itself, to help colorize a 1913 black-and-white photo of the work in progress. Matisse began work on Bathers in 1909 and unveiled the painting in 1917….That insight helps support research that Matisse began the work as an upbeat pastoral piece but changed it to reflect the graver national mood brought on by World War I.
In this way, they learned what the work looked like midway through its completion.