This is a very interesting way to paint wouldn’t you say? At his workstation an artist has in front of him a large tray of water which is surrounded by various jars of different colored paint/ink.
I believe the technique is called Suminagashi as is the ancient Japanese art of painting with inks onto water to create a marbled pattern in a whole manner of swirls, shapes and colors. The patterns are the result of color floated on either plain water or a viscous solution, and then carefully transferred to an clean absorbent surface, such as fabric or paper.
With the right equipment anybody can have a go at this and you can be sure that every painting you do will be different from the last one.