For every ounce of liquid product, there are 591 "drops". This is an important conversion to know when working with small batches. We receive many questions on how to translate "by %" with "drops". For example, many of our customers are interested in the right amount of preservative they need for their batch.
For lip gloss, you need to weigh your batch and then multiply that number by the percentage of preservative recommended (Cap 2 for oil based lip gloss recommends 0.8-1%). Convert the recommended percentage to a decimal number (1% = 0.01) when calculating.
For a lip gloss batch which weighs 200g, calculate 200 x 0.01 = 2.
This means you need to add 2 grams of preservative to your 200 gram lip gloss batch.
For pressed eye shadow, we recommend that you directly put the preservative in your liquid binder (whether it's the TKB MyMix Press Medium or jojoba oil). That means if you have 1/2 fl oz bottle of binder you'll only need 1-2 drops of preservative.
We highly suggest learning how to use a scale while formulating your recipes instead of just creating by drops. This will ensure more consistent batches each time you make them- especially if you decide to make larger batches.
You can easily search through Google as well "how many drops in [x]" or "how much is [x]% of [x]" to calculate these forms of conversions as well.