What is optical size?

Optical size refers to the perceived size of a typeface when printed or displayed, which can vary based on design features such as stroke weight, character width, and overall proportions. It is particularly relevant in typography where fonts may have different weights and styles that visually appear larger or smaller despite having the same nominal point size. Designers often adjust optical size to enhance legibility and aesthetic appeal in different contexts. This concept is crucial for creating effective visual hierarchies in graphic design and publishing.