I would have LOVED to have posted a success story accompanied with show-off photos to display fantastically blue coloured soap using indigo powder as the colourant…
…but that wasn’t to be.
I tried with two different kinds of indigo powder–one was still its natural green (which was meant for dying hair black), and the other was a deep blue powder. I thought the natural green one would turn blue when mixed with in the lye water but it didn’t happen. It stayed green. The resulting soap was the same dull green.
With the deep blue powder, initially it looked promisingly blue. In about 15 minutes after pouring, however, it started to turn rather decidedly black and gave off a mildly repulsive smell, not unlike rotten eggs. A day later the soap looked a deep algae blue-green. It’s kinda nice actually, but still too deep a colour.
I’ll post up photos soon. The results were disappointing, but I will keep trying to coax out a nice colour from the deep blue powder for my soap. Stay tuned.