Briefly describe what a color mode is, citing examples of common color modes and two of the most common modes. Include definitions of gamut and bit depth in your response.

Question

What will be an ideal response?

Answer 1

A color mode, or color method, determines the number of colors and combinations of colors used to display and print the image. Each color mode incorporates a numerical method called a color model, or color space, to describe the color. Photoshop bases its color modes on the color models that are commonly used when publishing images. Color modes also directly affect the file size of an image. Choosing a color mode determines which Photoshop tools and file formats are available.

When choosing a color mode, you must take into consideration many factors, including purpose, printing options, file size, number of colors, and layers that may be flattened in later conversions between color modes. Common color modes include RGB, CMYK, LAB, Indexed, and Grayscale, among others.

RGB (red, green, blue) is considered an additive color mode because its colors are created by adding together different wavelengths of light in various intensities. Also called 24-bit color, RGB color mode is used typically for images that are reproduced on monitors, projectors, slides, transparencies, and the Web.

CMYK (cyan, magenta, yellow, black) is considered a subtractive color mode because its colors are created when light strikes an object or image and the wavelengths are absorbed. Also called the four-color process, the CMYK color mode is used by most desktop printers and commercial printing businesses.

A gamut, or color gamut, is the range of printed or displayed colors. The color gamut on your monitor may not be the same as on your printer. For example, the RGB color mode displays a wider range of discernible colors than does CMYK. When you print an RGB image from your monitor, it must be reproduced with CMYK inks on your printer. The gamut of reproducible inks is smaller than what we see with our eyes, and any color that cannot be printed is referred to as out of gamut. In Photoshop, you will see an out of gamut warning if you select colors that have to be converted from RGB to CMYK. If you plan to send your image to a professional print shop, be sure to get details about color modes, models, and gamuts before the image is printed.

Once you choose a color mode, you also can set a bit depth. The bit depth, also called pixel depth or color depth, measures how much color information is available for displaying or printing each pixel in an image. The word bit stands for binary digit. A bit depth of eight means that Photoshop assigns eight binary settings for each color.