Color depth, also called bit depth, refers to the number of colors each pixel (and therefore its image) can display. As the color depth increases, the number of colors an image can display increases. Each pixel’s color information is stored in a certain number of computer bits—from 1 bit to 24 bits. In a 1-bit image, each pixel can display only one of two colors (black or white). In a 24-bit image, each pixel can display one of 16 million colors (224 or 2 colors for each bit). Images with a color depth of 16 million colors look best because they contain the most colors, but they also require the most memory to store and edit.
In Paint Shop Pro, you can create 2 color (1-bit), 16 color (4-bit), greyscale (8-bit), 256 color (8-bit), and 16 million color (24-bit) images. Many of Paint Shop Pro’s effect and correction commands work on 16 million color images only. Therefore, it is best to create most images using 16 million colors. After you finish working on an image, you can decrease its color depth and save it in another format.
Computer monitors also have a color depth that is determined by the monitor’s capabilities as well as the selected color setting. If you display an image with a higher color depth than the monitor can display, the image will have some color distortion. Some file formats limit the number of supported colors so that images display correctly on a variety of monitor types. For example, GIF images, a popular format for the Web, contain up to 256 colors (8-bit depth).
The number of colors actually used in an image is usually less than the color depth. For example, in a 16 million color image, the image is capable of displaying that many colors but may only use 50,000 colors. You can use the Image > Count Colors Used command to count the number of colors in a layer of the image.
To view the color depth of an image:
Do one of the following:
Look at the Status bar, which displays the active image’s pixel dimensions (the first two numbers) and color depth (the third number).
Press F9 to display the Overview palette, click the Info tab, and then view the Color Depth field.
Choose Image > Image Information, then look at the Pixel Depth/Color field.
To view the color depth of a monitor:
Choose Help > About Paint Shop Pro.
Click the System Info button.
Scroll down to the Video Driver Information section and look at the Number of Colors field.
To view the number of colors in a layer:
On the Layer palette, click the layer name that you want to check.
Choose Layers > Count Layer Colors.
Increasing the Color Depth of an Image
Decreasing Color Depth to 16 Colors (4-bit)
Decreasing Color Depth to 2 Colors (1-bit)
Decreasing Color Depth to 256 Colors (8-bit)