Character complexity
Our reserach shows that the simpler the character skeleton, the more legible the character.

This rule of thumb only applies when the shape of the character does not increase the rate of misreadings. In an investigation of the legibility of digits in a short exposure of three-digit strings at the peripheral visual field, we confirmed previous findings (Bernard & Chung 2011) that digits and letters benefit from having the most simple shapes. In other words, the shorter the morphological skeleton, the more legible the character.


These results somewhat contradict the approach applied by several renowned type designers whose focus on ensuring differentiation between characters may result in added features, such as cross bars and tails.

For the London Underground typeface, for example, Edward Johnston created a loop in the lowercase ‘l’ to differentiate it from the capital ‘I’. This resulted in a more complex letter skeleton, which in theory would lower legibility.

Our own studies (Beier & Larson 2010) showed that at greater reading distances, a tail on the ‘l’ results in fewer errors, that a cross bar on the letter ‘i’ can improve legibility, and that the letter ‘a’ should have a two-storey design.

Following this, we conclude that the advantage of the shorter morphological skeleton only applies in situations where the simple character skeleton will not result in a greater number of misreadings.

For more see:
Beier, S., Bernard, J.B. & Castet, E. (2018) ‘Numeral legibility and visual complexity’, Proceedings of DRS2018, Design Research Society, vol. 5, 1841-1854, Limerick, 25th-28th June.

Beier, S. & Larson, K. (2010) ‘Design Improvements for Frequently Misrecognized Letters’, Information Design Journal, 18(2), 118-137.

Other research findings


Centre for Visibility Design
The Royal Danish Academy of Fine Arts,
Schools of Architecture, Design and Conservation
School of Design

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