Colourise is an online service which can convert old photos to color photos instantly using artificial intelligence using Neural Networks . The website is from Singapore government. The above photo is taken from the web just for testing. There are articles which discus about colorizing black and white photos to color using photoshop. You may download those samples and try it on Colourise if you want to compare the result you got.
All you want to do it visit https://colourise.sg/ select the reCAPTCHA and upload the photo you want to colorize. That's all the we website will convert the black and white photo to color instantly. You can download the final result or the comparison of the photos.
The website do not store images that you upload for colorization.
The blog says they wanted to run this for the month of February and may extend it depending upon the usage. They have not taken it down yet. You can read more here.
The application is written using python. If you are a programmer and want to get the code you can get it from GitHub.
This code requires a working installation of Caffe and basic Python libraries (numpy, pyplot, skimage, scipy).
Colourise is using Generative Adversarial Networks (GANs) which includes two Neural Networks. For the learning purpose they have used Singapore based photos more, so the color reproduction will be more accurate for the Singapore based photos. But it works well with other photos too.