This is not your average, ordinary hair dyeing technique. This one's so different, it's done by hand painting the hair in sections on a large flat surface. Very unorthodox! Check it out:
It looks like that:

And it's done by hand:

It will give you a soft gradient effect:

Created by KL Christoffersen, the term "fluid hair painting" reflects the final results of the hair.

Check out a video of it below:
The technique is being copied elsewhere around the world too. From Sweden:
To Germany:
To Canada:
The results are pretty impressive:
Looks too hard to do it on your own!