the Case for Legibility, stated that "Printing with capital letters can be done sufficiently well to arouse interest and, with short lines, reading at a slowed speed is possible – but in principle too many factors of low legibility are involved." Other critics are of the opinion that all caps letters in text are often "too tightly packed against each other". Ambiguities Besides the aforementioned speed of reading, all caps is constitutionally prone to character-based ambiguities. Namely, the upper-case letters are globally simpler than their lower-case counterpart. For example, they lack ascenders and descenders. Since they are built from fewer positional and building elements (e.g. a smaller grid pertaining to minimalist digital fonts), they are more fragile to small changes. These variations, generally involuntary but sometimes induced on purpose, are caused by a misinterpretation (the information is transferred) or by a deterioration (the data is lost, in the analysis wording). They can occur horizontally and/or vertically, while misreading (without this extra effort or time), or during a delicate scanning of characters (from a damaged image that needs further contextual text correction). Depending on the typeface, these similarities accidentally create various duplicates (even quite briefly and without realizing it when reading). E.g. H/A, F/E or I/T by adding a bar; P/R, O/Q, even C/G from similar errors; V/U, D/O, even B/S while rounding the shape; and more deformations implying mixings. Adding digits in all caps styled texts may multiply these confusions, which is one aim of Leet (intentional pseudo duplicates) and can provide simple means of concealing messages (often numbers). See also Caps Lock Camel case Letter case Roman square capitals Shift key Small caps Unicase Uncial script References External links All caps – Practical Typography Typography Typesetting Capitalization