For the agricultural/topographic term see Keyline design

Keyline Design

Keyline design is a technique for maximizing beneficial use of water resources of a piece of land. The Keyline refers to a specific topographic feature linked to water flow...

A keyline, in graphic design

Graphic design

Graphic design is a creative process – most often involving a client and a designer and usually completed in conjunction with producers of form – undertaken in order to convey a specific message to a targeted audience...

, is a boundary line that separates color and monochromatic areas or differently colored areas of printing on a given page or other printed piece. The line itself, usually consisting of a black (or other dark colored) border, provides an area in which lighter colors can be printed with slight variation in registration. In traditional paste-up graphics workflows, keylines for cropping were often merely indicated on original artwork, and then images were stripped into the area manually with the keylines themselves being added as part of the process.