What is a good “recipe” to use as a starting point for mixing glow in the dark paint?
If the supplier of the base paint offers a starting formulation, use that. Otherwise, a typical mixture might be: 25% pigment, 20% calcium carbonate as filler, 55% clear base paint. All %’s are %’s of the weight, not the volume, of the final mixture. You may sometimes see a reference to a P:B ratio. This means Pigment to Binder, and it is just another way of describing a mixture. P:B ratios are always to binder without any additives or thinners.