The results are all over the map, but a few of the test images -- like the puppy and Monarch butterfly above -- look pretty good. The algorithms work using a few common sense rules (the sky is typically blue, dirt roads are usually brown and have a similar texture), and "hallucinating" a plausible colorized photo. But the results are far from perfect. For example, the neural net has a hard time coloring within the lines with more complex subjects like vegetables on a plate or keeping a heron bright white.

When it does hit the mark, however, it's impressive. In fact, 20 percent of the folks surveyed for a "colorization Turing test" were fooled into thinking that the images weren't monochrome to start. Unless you want to cry yourself to sleep though, don't look at what the algorithms do with anything from Ansel Adams. Trust me.