When writing first appeared, all letterforms were capitals. When metal type replaced handwritten type, both sets of letters were cut and cast. Printers stored majuscules in one big drawer, or case, and the minuscules in a companion case beneath it. Hence uppercase and l owercase . When a word is set in uppercase the outline is a rectangle, since all the letters align top and bottom.
Text set in all-caps requires constant attention and is slow to decipher.
Set in lowercase, each words shape varies from its neighbor, making recognition faster and easier. We recognize letter-groups by their characteristic profiles. Font Samples Proportionally spaced serif fonts are characterized by pronounced serifs, especially along the baseline, and letter spacing that varies widely. A proportionally spaced sans serif font lacks serifs and generally has a greater x-height and a more even letter spacing. The most obvious characteristic of a fixed width font is the very even, block-like spacing of the letters.