The most basic method of creating value in ink drawing is linear hatching. Fine parallel lines fill an area, so that from just a slight distance, we have the illusion of value. The closer the lines are, the less white paper shows, and the darker the value appears. Heavier line weight (pressing more firmly or using a bigger nib) also gives a darker appearance.
Crosshatching uses layers of hatching placed at an angle. Usually, the first layer would be vertical, the next horizontal, the next at forty-five degrees, and so on. This methodical approach can look a little mechanical, so artists often use variation in direction to add interest.