Color Channels In Photoshop
After I’ve droned on for pages about color in Photoshop, it might surprise you when I say that Photoshop is at its heart a grayscale editor. Oh sure, it offers an array of color conversion features and it displays and prints spectacular full-color images. But when it comes to editing the image, everything happens in grayscale. This is because Photoshop approaches every full-color image not as a single collection of 24-bit pixels, but as three or four bands of 8-bit (grayscale) pixels. An RGB file contains a band of red, a band of green, and a band of blue, each of which functions as a separate grayscale image. A Lab image likewise contains three bands, one corresponding to luminosity and the others to the variables a and b. A CMYK file contains four bands, one for each of the process-color inks. These bands are known as channels. Channels frequently correspond to the structure of an input or output device. Each channel in a CMYK image, for example, corresponds to a differen