I’m so happy to be able to write a little blurb about experiments in the studio again! I wish I had more time to do this amidst all the changes at work, but I’m happy for the occasional opportunity all the same. 
So how does spirulina fare as a stable, all-natural colourant in CP soap? I reckon it does pretty well, all things considered. Here’s what it looked like when I first sliced our Fiddler’s Green soap:
The powder itself looked a dark, deep blue-green which turned into this lovely fresh colour the day after I poured the soap into the mold.
Then 3 weeks later, this is what the colour looked like:
Not exactly stable, but still produces a good strong green. It lost most of its blue component, to take on a more mature, olive green kind of shade. Interestingly, the powder that is in the swirl on the surface of the soap seems to have stayed quite prominent:
I was hoping that it would retain its strong blue-tinged green, but I’m still happy with the results all the same. For the lowest layer of colour which was at its most concentrated, I used 25g of spirulina powder in about 2.6kg of raw soap (yes, that works out to be one rather expensive load of colourant for a bar of soap!)
It will be interesting to see what the colour looks like 6 months down the road. Will try to remember to post pics when I can.