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 Printing House for the Blind defines font sizes as: • 12 pt = regular print • 14–16 pt = "enlarged" print (not considered large print) • 18 pt and larger = large print • 18 pt 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 key characteristics of such fonts are: • 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==