VHT and Duplicolor are made by the same company, AFAIK, they are more like paint not dye. SEM is more like a paint too, but I've seen reallllly good results on leathers, and vinyls. I have not see it on any softer fabrics. I dyed a car seat with a fabric dye designed for synthetic fabrics with good results. You need to heat the dye to 180-200F for it to penetrate, the most difficult part was figuring out how to get an entire bench seat-back submerged in hot water.