Prepress Tip

Line Art

Line Art scanning is best defined as simply transferring pen and ink style drawings, clip art, and some pencil sketches into the computer system. Line Art has no shading nor color other than black. Line Art scanning is considered 1-bit scanning, that is the computer sees the image as either black or white.

Line Art scans, since they can only be black or white, do not have the luxury of anti-aliasing (a technique that makes smooth transitions between black and white by adding varying steps of gray), and therefore are prone to having jagged edges around curves when scanned at lower resolutions than the final output device. Therefore, you should not use Line Art style scanning to scan photographs or textured art.

Line Art should be scanned at as high a resolution as the final output device to eliminate the jaggie effects. In other words, if you have original art that is 5x7 and you're going to output at 5x7 on a 1200 dpi imagesetter, ideally it should be scanned at 1200dpi to achieve the best possible image. Note that if you original is larger than the final size, you should adjust your original scan resolution by the same ratio so as to no have more resolution than necessary.

The majority of line art that is scanned is usually some simple drawings or sketch used as a template for a more exact computer illustration. Using Adobe Streamline, or the AutoTrace function in Freehand, you can convert the line art scan into Encapsulated PostScript and thus allow you to increase the image to any size without the fear of the jaggies (of course, this is not a flawless step, you may well have to spend a considerable amount of time correcting for obscure autotracing errors).