Continuous tone

From Wikipedia, the free encyclopedia

A continuous tone image is one where each color at any point in the image is reproduced as a single tone, and not as discrete halftones, such as one single color for monochromatic prints, or a combination of halftones for color prints.

The most common continuous tone images are color photographs.

An example of a continuous-tone device is a computer screen. Here, any pixel can represent any color, because the color components of the pixel are analog and can vary in infinite steps, and hence do not need halftones to make the colors. Of course a computer cannot provide with infinite tone variations, being a digital device. In 24-bit color mode, it provides the monitor with 256 discrete steps for each color, for a total of 16,777,216 discrete colors. A purely analog video signal (one that has not been manipulated by a computer of any kind) can provide infinite tone variations inside its own gamut.

A halftone device, in contrast, uses discrete dots of color, which at a certain distance look closely like the intended color. Examples of this are inkjet printers. Magazines and most printed material also use this technique to create the colors, but in this case using the offset method.