Getting Started with Camera Raw: How to make better pictures using Photoshop and Photoshop Elements, Second Edition

Anatomy of an Image

The image that comes out of your camera is a grid of colored pixels. The color of an individual pixel in an image is usually specified using three numbers: one for the red information, one for the blue, and one for the green. If your final image is an 8-bit image, then 8-bit numbers are used to represent the pixels in each of these color channels. This means that any pixel in any individual channel can have a value between 0 and 255. When three 8-bit channels are combined, you have a composite 24-bit image that is capable of displaying any of approximately 16 million colors. While this is a far greater number of colors than the eye can perceive, bear in mind that a lot of these colors are essentially redundant. RGB values ...