Eli5: How do black and white movies/documentaries get turned into color?

Question

I’m watching all these WW2 documentaries and they all have it in color now. How did they do this? I kind of understand exposure and film but that’s about it.

In: Technology

Answer 1

There’s a 30 minute documentary about the colorization of footage and addition of audio for *They Shall Not Grow Old*, which explains the process. I’ll see if I can find it online.