Large-print (also large-type or large-font) refers to the formatting of a book or other text document in which the typeface (or font) are considerably larger than usual to accommodate people who have low vision. Frequently the medium is also increased in size to accommodate the larger text. Special-needs libraries and many public libraries will stock large-print versions of books, along with versions written in Braille. The font size for large print is typically at least 18 points in size, equivalent to 24px for a web CSS font size. Different sizes are made to suit different visual needs, with a common rule of thumb to be at least twice the minimum acuity size. Publishing standards The American National Association for Visually Handicapped (NAVH) provides the NAVH Seal of Approval to commercial publishers in the US, for books that meet their large print standards. (Lighthouse International acquired NAVH in 2010.) The standards call for: Maximum limits on size, thickness, and weight Minimum limits on margins Type size at least 14 point, preferably 18 point Sans serif or modified serif font recommended Adequate letter and word spacing Flexible binding recommended to allow open book to lie flat Additional guidelines The American Publishing House for the Blind defines font sizes as: 12 pt. = regular print 14-16 pt. = "enlarged" print (not considered large print) 18 and larger = large print 18 and larger, with other formatting changes = enhanced print In addition to enlarging type size, page layout and font characteristics can have a positive effect on readability. Fonts designed for legibility make it easier to distinguish one character from another. Some characteristics of such fonts are: Here are the primary things to think about when selecting a font for use by persons with low vision: The upper case "I" and Roman numeral "I", the numeral "1", and the lower case "l" should all look different from one another. The font should be wide-bodied with space between each letter. Letters which have a "bubble" inside them (known as a counter, such as o, d, g, e), should have ample space inside the counter. Punctuation should be rounded, large, and very visible. Font strokes should be solid and without gaps. Examples of more-easily read fonts are Antique Olive, Tahoma, Tiresias, and Verdana. Ratios Companies offering the large-print formatting uses diverse formats (also called ratios) to support the larger font size. Among these ratios, we