Almost 3 month update.. the colors are still bright, but are starting to fade a little. I tried the soap and it was absolutely disgusting. I used a high oleic recipe and I normally start to like this recipe around the 3 month mark, but this was just slime and sludge galore. Apparently the high amount of clays attract more moisture and the soap just doesn't dry between uses.
I also did another soap colored with clays, about a week ago.
Pink is just regular pink kaolin clay, used at 5g/100g oils (or +-1.5Tablespoon ppo).
Blue was 5g white kaolin clay with a pinch of indigo powder mixed in (my scale doesn't measure reliably for weights under 0.15g, so not sure how much I added exactly).
Grey/purple was 5g white kaolin clay soaked in 24g of alkanet infused in isopropanol and left to evaporate (2.4x as much as last time, though I used less of the clay -> 5g/100g instead of 7g/100g). I was hoping that using more infusion in making the clay would give me a darker, more saturated purple with less clay.. that doesn't seem to have worked out very well.
The purple in the new soap seems to stay more grey after a week of cure. Maybe it's the recipe -which is very different in FA profile, see below- maybe I shouldn't have used less clay soaked in more infusion.. I'm just not really sure. I do hope this soap will turn out to be less slimy than the other one!
I now know I can use indigo powder straight up mixed in clay if I want to incorporate blue into the design and I really don't need much to get a deep blue (it looked rather pale when mixed in clay, I'm sorry I didn't take a picture)
Lastly, weird enough the pink seems to look a lot more orange in the new soap than in the old, that could be because I used a bit less (5g/100g vs 7g/100g) or maybe the recipe plays a role and high palmitic/stearic brings out more of the orange tones while high oleic brings out more pinkish/reddish tones.
These are the recipes I used: the first test (in this picture on the right) was 25% coconut/75% HO sunflower - my go to recipe for tests, because it's cheap and I still like how it turns out after a reasonable amount of cure. The last soap was made with 50% (refined) shea butter, 30% RBO and 20% coconut oil. This one also accelerated like crazy and I'm not sure if it was the RBO, the clays or the EO blend (50% amyris, don't have enough experience to know if that one accelerates) or all of the above - I know it's not the high amount of butters, because I'd made a perfectly behaved batch of soap with 50% butters just the day before this one.