Software Colors
Color grading is the process of altering and enhancing the color of a motion picture or television image, either electronically, photo-chemically or digitally. The photo-chemical process is also referred to as color timing and is typically performed at a photographic laboratory. Modern color correction, whether for theatrical film or video distribution, is generally done digitally.
How color timing works
Traditional color timing was done by passing various intensities of red, green or blue light through a color film negative onto an intermediate positive stock to create a new image. A "white" light is passed through a series of dichromatic filters which splits the light into its various primary colors (red, green and blue). Zoom software. By incorporating a physical shutter system into the light path to vary the intensity of each primary color, the color timer could selectively alter the color results on the positive print.
Timers usually worked on a scale of 50 "lights" or "points", which are 50 steps of light intensity values for each of the primary colors. A neutral light setting would normally be 25-25-25 (red, green, blue), middle of the scale.
Additive Coloring
Because of the nature of color negative film, the coloring process is inverted.