There are five weights: Light, Regular, Medium, Bold, and Heavy. Each weight of course also comes with its own matching italic. The entire family began from the regular weight. It is strong, robust, and fairly dark in color.
The light version was added to give a slightly more delicate impression, something especially suited for fine book printing. It is a bit more condensed than the regular with and has less contrast. The medium weight works well the light for emphasis.
Bold is intended to be pared with the regular, but you may want to use it on its own for small amounts of text. Heavy is extra everything: thicker, louder, and has high stroke contrast. It is perfect for headlines or simply to get the reader’s attention.
Read on: Character Set