The dyes I use for resin are all powders not liquids. If you want to absolutely get the "right" one then check out this brand: https://www.amazon.com/Stick-Fast-Po.../dp/B00E39XY5C
That being said, make-up dye powders also work just fine like these https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1