Ebru has been a part of the Turkish art scene for centuries, and has long been a specialty of Istanbul’s dervish orders. Contributing to the technique’s popularity is the fact that it’s easy to learn; even an absolute beginner can create an impressive piece of art. Basically, you drip paint on top of water, use needles and brushes to make swirling designs, and then transfer the finished work onto paper. The paints are treated with ox gall to lower their surface tension, allowing them to float, and the water’s properties result in fluid, hypnotic patterns.
A web site on this stuff http://istanbul.for91days.com/2013/06/20/an-introduction-to-turkish-marbling/