Suminagashi is a fascinating Japanese paper marbling technique that uses water-based sumi inks floated on plain tap water. The word suminagashi literally means spilled ink. It is very different from acrylic marbling in that the thin boku inks (black, red, yellow, blue--a very limited palette) are more fluid and form thin concentric rings rather than fat rounded circles when dropped into the marbling tray. Also, the ink patterns absorb best on thin rice paper and not on standard printmaking or watercolor paper. This means that when I'm all done, I have to glue my delicate marbled rice paper to a heavier paper (if I want to further paint on it and develop it into a finished painting).
The advantage of suminagashi is that it only requires a few inches of tap water in the marbling tray, so the cumbersome and time consuming process of blending carageenan 24 hours in advance of marbling is no longer an issue. This makes suminagashi more portable when you want to take it on the road and teach it to others!
This summer I taught myself how to combine suminagashi and acrylic marbling into one painting. The trick is to do the suminagashi marbling first since it is often more pale than the acrylic marbling. Once the suminagashi marbled paper is dry, I then treat the paper with alum for acrylic marbling and marble a new pattern on top of the suminagashi pattern. The two patterns, while different, are often complimentary as they "criss cross" each other on the paper.
I will be teaching several suminagashi workshops in 2017; most are one day workshops in which we create stacks of marbled rice papers. But I aim to teach more of the two day suminagashi workshops (like the one I'm offering in July at Sitka Art & Ecology Center) because I'm excited about teaching others what comes AFTER the marbling process---how to turn patterns into paintings.
In the meantime, here is a step by step slideshow depicting how I turned one of my "combo" marbling papers into a finished painting called "Expecting To Fly #2".