Thank you! There are four different colorants in these photos, two in each brownie pan. I start with enough batter for twelve and then add more colorant each time I pour some off. I came up with a spreadsheet that accounts for how much colorant is left from the previous round and how much batter is left, and it calculates how many drops to add to get the percentage I am after. The spreadsheet can be used for larger batches too if you know the total oil weight, and the weight and concentration of colorant in whatever you use to disperse it. I’m going to share the spreadsheet, I want to make it a little more user friendly, but others might find it useful.
The thought of doing it makes my head hurt.. thanks for sharing your hard work!