Typefaces look best when proportioned for the sizes at which they will be used. As type gets larger strokes should be lighter, spacing tighter, and hairlines thinner. Metal fonts were crafted for a single size. But digital fonts can be scaled to any size, allowing display faces to render text unreadable and text faces to be swollen into ungainly brutes. This problem is most obvious in high-contrast modern faces where hairline serifs can turn into slabs when scaled too large or disappear when scaled too small. To address this problem digital type designers craft optical weights; fonts suited for a specific size range.
The Sybarite type family is a fat face with matching italics in four optical weights. Small for sizes below fourteen points, medium for sixteen to twenty-four points, large for twenty-four to sixty points, and huge for sixty points. Naturally there is some overlap in these ranges based on the preference of the end user. And designers can use a heavier font to knock out text or a lighter font when working with uncoated papers that have a strong inclination to ink gain.