I just returned from a 4 day workshop by Ann Johnston on Dyeing with Black Dyes. We made our own and use some commercially prepared. Then she encouraged us to desgin! Wow! What things emerged as we gathered courage by the second day.
We dyed on multiple types of fabrics including silks. The results were so wide and varied that we learned much in the 4 intense days. Here are some of my pieces. The orange is a piece that I overdyed with black dyes later to see what happened when I did that. The first piece there is from a stamp that I made from plexiglass and craft foam. The middle is from a roller run over fabric on top of some bubble wrap.