Zero digital noise photography

A few years ago I had written about Guillermo Luijk’s technique to remove completely noise from digital photos. We know that this is a difficult task, but his solution is relatively simple:

1. Shot the scene in a correct exposure according to our usual workflow;
2. Repeat the shot now reducing shutter speed by 4 f-stops that will be corrected in the RAW development (this grossly over-exposed shot will keep shadow details without digital noise);
3. Blend in some way both images obtaining a free of noise final image.

Guillermo Luijk had published his software application and I did not mention it. So, let me correct this error and give you Zero Noise.