Dot Gain

Change in size of the printed “dot” (really printed area coverage) relative to that required to reproduce the specified tint..

• Dot gain can occur on all types of printing devices including continuous tone devices such as dye sublimation printers.

• In conventional printing dot gain can occur in multiple stages of the process. It can occur when the image is output to film on the imagesetter (this is usually called recorder gain). It can occur during plate exposure and as well as on the press.

• Dot gain will always occur, but regardless of the process, it will need to be controlled or corrected for to obtain predictable color reproductions.

• It has been conventional to specify standards for acceptable dot gain for different types of paper art, matte, uncoated and newsprint).

• Dot gain from film to print has two components. One is the mechanical process of the dot expanding while being printed.

• The other is an optical dot gain due to the fact that the ink film casts a shadow on the nonimage areas of the paper.

• Laminate proofing systems such as Cromacheck exhibit optical but not mechanical dot gain.

• A tone reproduction curve gives to relationship between tonal value and dot gain.

• Dot gain is often compensated for during conversion to CMYK.

• Photoshop by default assumes SWOP standard inks on coated paper with 20% dot gain.

• Dot gain on web presses is normally higher than sheetfed.