Lapis
A decent begining manual for color therapy is included in a great book by Stanley Burroughs called Healing for the Age of Enlightenment. It explains the process. I have used it and it definatly has an effect. It has brought about some interesting spiritual effects in my life but I developed an intolerance to the heated gels and had to quit. The headaches were too much. If I can figure out a way around this I will start up again because it truly is incredible. The color green was the most beneficial for me.
One of the best contributors in the colory therapy field was Colonel Dinshah Pshadi Ghadali. He took this therapy to a whole new level and Stanley bases his work on Dinshah's knowledge.
Edgar Cayce also utilized color therapy.
Anyone wanting to try color therapy could track down Stanley's book in their area and purchase a stage light that accepts gel filters. Stanley reccommends the exact filters to use based on their purity.