This month MyHeritage are offering a black and white colourizing service for free. It work very well on some images and it’s based on open source artificial intelligence.
The featured photo above is one I have written about previously here.
I have also discovered it’s possible to use the tool without going to My Heritage by visiting the authors Google Lab page, it looks a bit scary, but this YouTube video walks you through the process.
Here is the other photo from the article mentioned above.