Slab serif

In typography, a slab serif (also called mechanistic, square serif, antique or Egyptian) typeface is a type of serif typeface characterized by thick, block-like serifs. Serif terminals may be either blunt and angular (Rockwell), or rounded (Courier). Slab serifs were invented in and most popular during the nineteenth century.

Slab serifs form a large and varied genre. Some such as Memphis and Rockwell have a geometric design with minimal variation in stroke width: they are sometimes described as sans-serif fonts with added serifs. Others such as those of the Clarendon genre have a structure more like most other serif fonts, though with larger and more obvious serifs. These designs may have bracketed serifs which increase width along their length before merging with the main strokes of the letters, while on geometrics the serifs have a constant width.

Display-oriented slab serifs are often extremely bold, intended to grab the reader's attention on a poster, while slab serifs oriented towards legibility at small sizes show less extreme characteristics. Some fonts oriented towards small print use and printing on poor-quality newsprint paper may have slab serifs to increase legibility, while their other features are closer to conventional book type fonts.

Slab serif fonts were also often used in typewriters, most famously Courier, and this tradition has meant many monospaced text fonts intended for computer and programming use are slab serif designs.

Slab serif typefaces appeared rapidly in the early nineteenth century, having little in common with previous typefaces. As the printing of advertising material began to expand in the early nineteenth century, new and notionally more attention-grabbing typefaces were needed. Poster-size types began to be developed that were not merely magnified forms of book type, but very different and bolder. Some were developments of designs of the previous fifty years, such as bold and ultra-bold types such as fat faces, which were related to Didone types but much bolder. Others had completely new structures: reverse-contrast letterforms, sans-serif and slab-serif were new departures at this period. Some of the designs appearing around this time may be based on signpainting traditions, or vice versa.

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