by Katie Middleton This is the gold standard for color education. The second edition includes updated chapters on pigment sourcing, tattoo covering, and how lighting affects makeup on film sets. It is available in digital format via subscription services like Perlego.
Makeup is essentially the management of light. Professional makeup theory covers how different light sources affect color payoff: makeup theory pdf
This is often overlooked. A theory PDF should explain why cream products are better for dry skin and powder products for oily skin. It should cover the pigment load of different brands and how to mix mediums (e.g., using mixing liquid to turn shadow into liner). by Katie Middleton This is the gold standard