If this interests you then you might like to check out “They Shall Not Grow Old”[0] - a Peter Jackson movie which is based off AI/ML restored[1] WW1 footage with color, sound, and dialog added to silent B&W original stock.

[0]: https://en.m.wikipedia.org/wiki/They_Shall_Not_Grow_Old [1]: https://m.youtube.com/watch?v=IrabKK9Bhds