When a typeface is intended to be used at some specific sizes only (large on billboards or small in printed books), some details can be optimized for each situation, resulting in optical size styles such as Text, Caption, Titling, or Display.

For text styles, aspects such as lower contrast and simpler details have been proven more efficient for reading small texts (especially if they are printed on rough surfaces), while display styles can carry elaborate details as they are seen in larger sizes.