For the CMYK color scheme, color specifications must be enclosed in quotation marks. For all other color schemes, the quotes are optional. You can freely intermix color-naming schemes in your programs ...

RGB (short for Red, Green, Blue) An RGB color space is any additive color model. The main purpose of the RGB color model is for the sensing, representation, and display of images in electronic systems ...

Red, green, and blue (RGB) are the primary colors used in the LEDs that can be combined to create just about any other color, which can usually offer up to 16 million color combinations.