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Saddle stitching

A printed document is saddle stitched by stapling its sheets at the fold of the spine, over a mechanical 'saddle'. Saddled stitching is used for thin magazines, brochures and journals.

Thicker documents often have to be perfect bound.

See also: perfect binding

Show-through

Showthrough happens when the printed image from one site of a sheet of printed paper shows through to the other side. Usually occurs on thin newspaper or magazine printing paper. An 'off-white' sheet is often used to help reduce this in thinner paper stocks.

Substrate

Any material or surface that is to be printed on. For example, paper is a printing substrate. Other printing substrates can include plastics, card and even metals.

Spot color

A spot color is an 'extra', or 'special' color that is used in addition to the CMYK four color process. The extra ink is added to its own roller on the printing press, so as to more accurately print certain colors that are hard to reproduce with CMYK inks. There are a number of companies that manufacture and specify spot colors, most common of these is the Pantone color matching system.

Spot colors are often also used in predominantly black and white publications, where it would be too expensive to add a CMYK graphic element. Advertising is often sold this way and a charge is made for each extra spot color. It is for these reasons that companies often have several versions of their company logo as part of their corporate identity, full color, mono and a spot color version.

See also: Pantones, definition of corporate identity.

Stochastic screening

Stochastic screening, also known as frequency modulation (FM), is a relatively new method of reproducing halftone screens.

Traditional halftone screens - also called amplitude modification (AM) - simply adjust the size of the dots to reproduce tonal variations in images. Larger dots produce darker tones, whilst smaller dots reproduces the lighter areas of an image.

Stochastic screening aims to achieve a higher quality reproduction of graphic images by using complex mathematical algorithms to modify the number of halftone dots. By varying their position and clustering of halftone dots, stochastic screening can achieve a smoother tonal reproduction and a higher quality printed reproduction of image detail.

Another advantage of using a stochastic screening method is that it can have a dramatic effect on reducing the potential for moire patterns to appear.