Light and Shading: The Five Zones of Form

Shading explains form

A circle drawn in outline is just a ring, but leave one side light and darken it gradually toward the other, and it begins to look like a ball. Shading is not decoration; it tells the viewer which way each surface faces. Surfaces facing the light are bright, and those turned away from it are dark. So rather than thinking of shading as filling an area with pencil, think of it as judging how much light each surface receives and recording that amount. You will be far more accurate. This guide is written with pencil drawing in mind, but the same principles apply directly to color and digital work. It is best to practise first with white objects, because once color is involved it becomes hard to tell value and hue apart. A white paper cup or a single egg makes a perfectly good subject.

The five zones of light

When light falls on a sphere, its surface generally divides into five zones. Learn this sequence and you have a framework for shading any object.

• Highlight: the small spot or area reflecting the light most directly
• Light side: the broad lit area, darkening slightly away from the highlight
• Core shadow: the band where the surface turns from the light, looking darkest on the shadow side
• Reflected light: weak light bouncing off the floor or nearby objects that slightly lifts the shadow edge
• Cast shadow: the dark shape the object throws onto the floor or other objects by blocking the light

Settle on one light source

Shading usually looks wrong when it was applied without deciding where the light comes from. Before you start, choose one direction, such as upper left or front right, and mark it with a small arrow in the corner of the page. For first practice, nothing beats switching off the other lights, turning on a single lamp, and lighting a simple object such as a white ball, an egg or a cup from above at an angle. Light from several directions creates multiple shadows and blurs the core shadow, which makes the form hard to read. When working from photos, picking one lit by a single strong light makes practice much easier.

Make a value scale

Knowing the range of values your pencil can produce makes it easier to plan shading. Divide a long rectangle into five boxes, leave one end as the white of the paper, shade the other end as dark as your softest pencil allows, and fill the middle boxes so they step evenly between the two. Once that is comfortable, extend it to nine boxes. While drawing, squint at your subject. Detail drops away, leaving only light and dark masses, so it becomes easier to judge which box each area belongs to. Viewed like this, even colored objects can be read purely for value.

Ways to build tone

There are several ways to make tone with a pencil, and you can combine them. Whichever you use, building up light layers gives a more even and richer tone than pressing hard all at once.

• Hatching: close parallel lines in one direction
• Cross-hatching: layering parallel lines in another direction to go darker
• Contour lines: strokes that curve with the surface to add a sense of volume
• Blending: shade first, then smooth it out with tissue or a stump

Rules of shadows

Shadows behave in consistent ways. The exact point where an object touches the floor receives almost no light, making it the darkest spot in the drawing. Put this contact shadow in firmly and the object sits solidly on the ground; leave it out and it seems to float. A cast shadow is darkest and sharpest near the object and grows paler and softer as it moves away. Shadows stretch away from the light source and lengthen as the light gets lower. Reflected light lifts the shadow side a little, but it must never become brighter than the surfaces lit directly.

Common mistakes

Habits that often appear when people first add shading. Check for them before you call a drawing finished.

• Darkening along the outline like a border: let the light direction decide where it is dark
• Making reflected light too bright: keep it a step or two darker than the lit side
• Shading the darkest areas first: build middle tones, then darken at the end
• Covering everything in a similar grey: decide clearly where the lightest and darkest areas are
• Forgetting the contact shadow: darken the point where the object meets the floor