Two ancient traditions in one! Quite a unique experience. Time was an interesting factor and smell was certainly part of the process.
Once I created a vat of the indigo bath, I processed just about every sheet of unsized handmade paper I had around me. Hemp, flax, abaca, kozo and cotton. The pieces that could withstand dipping were dunked and the others were saturated with the indigo bath on a huge brush. There was always a distinctive urine-like smell in the room but not unpleasant. Once the liquid indigo touched the fibers of the paper they were a bright green. Over a period of about 10 minutes they evolved into the final blues. This timing is shown in the photograph transpiring over a time period of about 15 minutes. The most recent dunking pieces were the greens. Here are a few finished pieces using the little squares.
My conclusion was that I could get some blues that I can’t get with acrylic paint but the control of specific blues was more serendipitous.