Character-related factors

Notation

Capital (upper-case) letters tend to vary less significantly than lower-case letters. The top parts of capital letters, in particular, which are more important for reading than the lower parts, are easier to confuse than lower-case letters.

THIS MEANS THAT TEXTS WRITTEN IN CAPITAL LETTERS ARE MORE DIFFICULT TO READ THAN TEXTS WRITTEN IN A MIXTURE OF UPPER- AND LOWER-CASE NOTATION.