The formulations in my book, Make it Up: The Essential Guide to DIY Makeup and Skin Care, use a combination of weight and volume measurements, with volume measurements being used mostly for powders and pigments that are used in small amounts. This was a deliberate choice to increase the accessibility of the formulations—readers only need a scale accurate to 1g and a set of tiny measuring spoons. The precision required to weigh out 1/64 tsp of a powdered pigment would require a relatively pricey scale compared to a $5 set of measuring spoons.
The formulations in the book were developed as they are shared. This means there are no fully-by-weight versions of the formulations, meaning I don’t have some sort of document with by-weight versions I can share. I tested all the projects thoroughly and am confident they work as written and shared, even with the slight variations inevitable with volume measurements.
If you want to make the formulations by weight that is very understandable, but you will have to the conversions yourself. I do not have any sort of master volume-to-weight conversion chart I can share.
I would recommend by discerning an average per-teaspoon weight of each ingredient. For example, weigh out one teaspoon of titanium dioxide five times, and then average out that weight. From there, you can divide that number as required to get an average weight per half teaspoon, quarter teaspoon, etc. It is very important that you do this for every single ingredient as they will have different densities.
Good luck & happy making!
Posted in: Makeup & Cosmetics