Line: The First Element of Art

You have drawn lines your whole life — on paper, in sand, on a foggy window. This lesson gives that mark a name and teaches you six kinds of line marks and three jobs a line can do inside a drawing or painting: contour, gesture, and implied. By the end, you will be able to spot a contour line in a real painting by Leonardo da Vinci.

You have already drawn hundreds of lines — on paper, in the sand at a beach, or with a fingertip on a foggy window. You have never had a reason to stop and ask what a line actually is — that is the whole job of this lesson: not to teach you a new skill, but to teach you to notice and name a mark you already know how to make.

A line is a mark that connects one point to another. Touch a pencil to paper at one spot, drag it to a second spot, and the mark left behind is a line — the most basic mark any artist can make. Every drawing, painting, sculpture, and building this unit studies starts, in some sense, with lines: an artist plans a composition with lines, blocks in a sketch with lines, and often finishes a work with lines still visible on its surface.

Because a line can be dragged in so many different ways — fast, slow, straight, wobbly, pressed hard, barely touching the page — a line can look very different from one artist, or one moment, to the next. The next screen sorts those differences into a short, memorable list.

Here are six kinds of line marks used throughout this course:

• Straight line — a line that does not bend or curve at all, like the edge of a ruler or a tightly pulled clothesline.
• Curved line — a line that bends smoothly, with no sharp corners, like the arc of a rainbow or the shape of a rolling hill.
• Thick line — a bold, wide mark, often made by pressing hard or using a wide tool, like a heavy stroke from a marker.
• Thin line — a fine, narrow mark, often made with a sharp point and a light touch, like a line from a mechanical pencil.
• Broken line — a line that is interrupted by gaps, so it stops and starts rather than running continuously, like a dashed line painted down the center of a road.
• Zigzag line — a line that changes direction sharply and repeatedly, snapping back and forth like a bolt of lightning.

These six words describe what a line mark looks like. The next screens describe something different: the job a line does inside a drawing or painting.

Say this chant aloud, a few times, until you know it without looking:

"Line is a mark that connects one point to another; it can be straight, curved, thick, thin, or broken."

As you say each kind of line, trace it in the air with a fingertip — a straight slash for "straight," a smooth arc for "curved," a wide swipe for "thick," a tiny flick for "thin," and a few short choppy strokes for "broken." Say the words in this exact order every time — the order is part of what you are memorizing.

Two lines can look exactly the same — say, both curved and thin — and still be doing completely different work inside a picture. Here are two of the most important jobs a line can take on.

A contour line is a line that traces the outer edge of a shape or form, showing exactly where it begins and ends. When you trace all the way around your own hand on a piece of paper, every stroke of your pencil is a contour line — it follows the true edge of the hand, finger by finger, with nothing added and nothing left out.

A gesture line is a quick, loose line that captures the overall pose or movement of a figure, rather than its exact edges. If an artist has only a few seconds to sketch a runner sprinting past, there is no time to trace every precise edge — instead the artist makes a few fast, sweeping marks that capture the feeling of the runner's motion: the lean of the body, the swing of the arms. A gesture line is loose on purpose; being exact is not its job.

An implied line is a line that is only suggested — by a row of objects lining up, by an edge where two colors or values meet, or by the direction someone is looking or pointing — even though no continuous mark is actually drawn. Picture three birds perched in a row on a telephone wire, each one separated from the next by open air. No one drew a line connecting them, yet your eye connects them anyway, because they line up. That connecting line exists only in the way you look — it is implied, not drawn.

Contour, gesture, and implied line will come up again and again — an artist chooses which job a line should do based on what the artist wants a viewer to notice.

Step 1 — Locate the edge. Look at the outer edge of Mona Lisa's face and hands — this is where her form meets the space around it. Step 2 — Name the kind of line. This edge is a contour line — it traces exactly where her face and hands begin and end. Step 3 — Describe the quality. Da Vinci rendered these contour lines soft and gradually blended, rather than sharp and hard, giving her face a gentle, rounded look — the lines themselves are mostly curved, not straight. Result: The contour line of Mona Lisa's face and hands is a soft, curved line that shows exactly where her form ends and the background begins.

Step 1 — Look for movement clues. Notice the arms and hands of the apostles seated around the table, reacting with surprise. Step 2 — Name the kind of line. The loose, sweeping shapes of their raised arms and gesturing hands are gesture lines — they capture motion and reaction rather than exact outlines. Step 3 — Look for a line that is not literally drawn. Many of the apostles' arms, hands, and gazes all point roughly toward the center of the table, where Jesus sits. No single mark connects them, but your eye follows the direction they share — this is an implied line, leading the eye straight to the center of the composition. Result: Da Vinci combined loose gesture lines in the figures with straight architectural lines in the room, and used an implied line — formed by pointing arms and turned heads — to draw your eye to the center of the painting.

Work each one out loud on your own, then check your answer against the table below.

This lesson closes with a close look at a real work of art, using the words you just learned.

Look for one example of a contour line, and one example of a different kind of line — curved, gesture, or implied — somewhere else in the painting. Notice exactly where each one appears. You will be asked about both below.

You might be tempted to assume a thick line must be straight, or a thin line must be curved. Don't — thick and thin are about how wide the mark is; straight and curved are about whether it bends. Any line can be thick or thin, straight or curved — they mix and match.

You might be tempted to confuse a broken line with an implied line, calling a dashed line "implied" because it has gaps. Don't — a broken line is still actually drawn; it just has gaps in the mark itself, like a dashed line. An implied line has no mark drawn at all; your eye supplies it from clues like objects lining up.

You might be tempted to call any quick sketch a "contour," labeling every line in a loose, fast sketch "contour." Don't — contour lines are careful and exact; they trace the true edge. A quick, loose sketch that only captures pose or motion is a gesture line, even if it is fast to draw.

You might be tempted to think every line in a picture must be a mark someone actually drew, insisting an implied line "isn't really a line" because nothing is drawn. Don't — an implied line is still a real kind of line; artists use it on purpose. It just does its job through clues, like a row of objects or the direction of a gaze, instead of through an actual mark.

You might be tempted to mix up zigzag and broken, describing a lightning bolt as "broken" because it looks jagged. Don't — a zigzag line is one continuous mark that keeps changing direction sharply; think of the shape, not gaps. A broken line is interrupted by real gaps, like a dashed line. Lightning is zigzag, not broken.