A curve, or color curve, is a graphic representation of color and tone. Adjustments to the angle and slope of the curve. The curve starting point plots a straight line from the lower left corner representing blackBlack is the fourth color in the process of four-color printing. The "K" in CMYK. Black adds tonal d... More and the upper right corner representing white in an RGBWhat is RGB? RGB stands for Red, Green, and Blue. These are the colors of light. Monitors, TVs, and ... More image.