Curves can usually be applied to all channels together in an image, or to each channel individually.
Applying a curve to individual channels can be used to stress a colour. This is particularly efficient in the Lab colour space due to the separation of luminance and chromaticity, but it can also be used in RGB, CMYK or whatever other colour models the software supports.
- The gimp manual
- Adobe web site on curves in Photoshop
- Detailed instructions on the usage of the 'curves' and 'levels' functionality of image editing software; PhotoshopEssentials.com
- Margulis, Dan (2005). Photoshop LAB Color: The Canyon Conundrum and Other Adventures in the Most Powerful Colorspace. ISBN 0-321-35678-0.