find: Ratio 1:1, the content is enlarged on a single (1) portrait page and the common typological size is 18 points. Ratio 1:2, the content is enlarged on two (2) landscape page and the common typological size is 18 points. Custom ratios, the content is enlarged on multiple landscape pages and the common typological size is 28 points. History Among the first large print book publishers, the Clear Type Publishing Company published a collection of books in 36 point type, circa 1910. The Ohio-based company specialized in large print, publishing books in 36pt and 24pt. In 1914 Robert Irwin produced a series of textbooks in 36 point, for low-vision children in Cleveland, Ohio schools. This type proved to be too large and was soon abandoned for the more popular 24 point. Research sponsored by Irwin in 1919 indicated 24 point type to be the most readable of the sizes evaluated. Further research by others in 1952 and 1959 supported 18 point or 24 point type. In the UK in 1964, Frederick Thorpe began publishing standard print titles with type approximately twice the size of the original printing. The books were given plain dust jackets, color-coded to indicate categories like mysteries (black), general fiction (red), romances (blue), Westerns (orange), etc. These physically large editions were reported to be difficult for some readers to handle. In 1969, Thorpe's company, Ulverscroft, began producing the books in 16 point type and normal-sized bindings, which the company claims increased the acceptance of large print in public libraries. 16 point type is smaller than the minimum recommended by the American Council of the Blind, which recommends 20 point, with 18 point as a suggested minimum. In 2008 the W3.org released the WCAG 2.0 web accessibility standards, which define large text as 18pt, which is 24px in CSS. Further, the standard specifies that users must be able to increase the font size 200% without breaking content. Today large print editions of some current books are published simultaneously with regular print editions by their publishers and usually feature the same full-color jackets and jacket design. Public libraries often have large print sections, and many bookstores carry some large print editions. Recent developments Since 2005, some companies have begun offering a variety of font sizes for large print books. See also Accessible publishing Legibility References Blindness Typography