Can you get the paints from Galen Berry? I had good results on fabric with
these. Try this site:
Also the fabric you use has a lot to do with the vibrancy. The smoother and
higher thread count fabrics seem to show the colors best. I had problems
with pre colored fabrics. I think the colorfasting process puts a barrier to
the marbling process. You can always dye your own colors. I had some great
results from shirting fabric. It was smooth, white and 100% cotton.
Regarding the lumps: Do you use a blender for your carrageenan? If not or
not blended long enough could account for lumps.