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Halftones and tone transfer curves PSF for z/OS: User's Guide S550-0435-04 |
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Halftones and tone transfer curvesHalftones are used to convert images (such as photographs, drawings, logos, or charts) from the continuous tones that you see on a monitor into a pattern of dots that a printer can put on paper. Tone transfer curves are used to modify the values of a particular color component and thus adjust the look and feel of some of the colors. For example, you can apply a tone transfer curve to emphasize the brightest parts of an image. Halftones and tone transfer curves are used with both color and grayscale print jobs. There are several different kinds of halftones, including clustered-dot, stochastic, and error diffusion. For simplicity, this discussion only covers clustered-dot halftones. Clustered-dot halftones are generally characterized by:
Tone transfer curves are most often used to offset the effects of dot gain. Dot gain is the tendency for printed dots to be larger than intended, often because of the way ink reacts with paper. If the ink soaks into the paper and spreads out, the resulting dot is much larger (and possibly much lighter in color) than the printer intended it to be. Tone transfer curves can increase or reduce the amount of ink used in proportion to the dot gain. |
Copyright IBM Corporation 1990, 2014
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