Curves
From The Glossary of Digital Photography
A function in Photoshop used to adjust images by mapping pixels into different tonal values. The adjustments can be made for the entire image or for each channel individually. In the case of RGB images, there is a choice of the three channels (RGB) or the entire image. In the case of CMYK images, there is a choice of the four-color channels or the entire image. The actual function is an x-y coordinate system with the input (original) values across the x-axis and the output (changed) values across the y-axis. Curves allows for detailed adjustments that are more precise than using the levels tool. Since tonal values can be changed for each color, the photographer is able to make creative changes to the colors as well as changes designed to make the image more pleasing. See also RGB; CMYK
