Hatching is a great way to create value with both pen and unblended pencil. Here are a few variations of fast and effective hatching technique.
Make sets if tiny overlapping circles or squiggles. This creates a rough, loose organic texture. To darken, and more squiggles over the squiggles. Blur your eyes to find areas of uneven value and fill these with additional marks.
Start with a series of loose scribbles.
To deepen the value, add more squiggles on the squiggles.
You can use parallel lines to fill an area with tone. By varying the spacing and width (pressure) of the lines you can make areas darker or lighter. Use your non-photo blue pencil to add a few parallel lines before you start to help prevent your lines from drifting to a new angle across the hatched area.
If it will take multiple strokes to make a longer line, try leaving little irregular spaced gaps between one line and the next instead of overlapping the strokes. Overlap strokes often make irregular blotches while irregular spaced gaps add a little sparkle to your technique.
To create long lines, stagger the break point along an irregular margin.
Leave a little gap and complete the line.
If your lines show through in your final drawing, their direction can help to show changes in the planes of the object you are drawing. See Showing Planes with Line Angle. Alternatively, you can keep the line direction consistent across planes, reducing detail in the shaded area and allowing it to recede into the background.
People see bold and widely spaced lines as “lines”. If you make the lines lighter and closer together, you can achieve the same value and people will ignore the “lines” and read them as an area of tone.
Can’t draw a straight line? Patch hatching is for you. This technique is very vast and creates a dynamic and interesting texture. Create small sets of interlocking lines, varying the angle of each set.
Draw small sets of interlocking lines, changing the direction of each set.
Darken areas by adding cross hatching sets over the first lines. Try to avoid lines crossing at right angles.
Continue to cross hatch to build up the values you want.
Cross hatching is a fundamental technique to deepen values. There are a few subtleties with this technique that are often overlooked. The most important is to watch the angles of the cross lines, avoiding right, and sharply acute angles.
Start with a set of parallel lines.
Add a second set at an oblique angle to the first set.
Avoid cross hatching at a right angle. This looks like a screen door and is distracting.
Avoid hatching lines that are at an angle that is close to that of the first set. This creates odd patterns of dark and light.
Instead of keeping the lines parallel, you can wrap them around a curved surface. As you draw, imagine the lines wrapping around the curved surface. The lines can fan out from a pinched shape to fill a larger area. As they do, the lines may become so spaced from one another that they no longer read as an area of tone but individual lines. Resolve this by making a second set of lines from the outside of the broad edge toward the narrow point. You can also cross hath these contour lines.
Fan contour lines from a narrow pinched shapes into open shapes, Contour lines can wrap around rounded forms.
Add a second set of smaller lines from the larger edge toward the smaller.
Cross hatching lines can also wrap around the contours.
You can also add additional levels of hatching to farther deepen values.