A form of additive color mixing using the three primary colors of light: red, green, and blue. Often used with X-Rays, cyc lights, and LEDs. See the collaborative article: Color Mixing, Lighting. Image from http://www.lightlife.de/farbtheo.htm The attached .zip file is an Excel workbook that shows approximate RGB equivalent values for Roscolux, LEE Filters, and GAMcolor color media. Note that the accuracy will vary depending on intensity, color, and source of the the specific RGB colors.