Chiaroscuro Lesson

The intent of this lesson is to highlight the relationship between drawing and painting. More particularly, I'd like to show how an understanding of chiaroscuro (the illusion of 3D space on a 2D surface using light and dark shapes) relates to understanding how to make more educated choices when creating a line drawing.  This lesson contains most of the fundamentals anyone would need to know to draw or paint.  The only missing element is practice.  If you know all these facts well and are able to see them in the world around you, then you just need to learn how to juggle them efficiently as you draw and paint.

Before the tutorial, here are some vocabulary words and basic definitions:

• cast shadow- this is the kind of shadow that chases you on a summer day
• form shadow- this is the kind of shadow that doesn't get any light. Like the dark side of the moon.
• value- the quality of lightness or darkness of a mark or shape.
• edges- the boundary between shapes.
• highlight- the reflection of the light source on an object.
• light side- the part of an object receiving direct light
  
• dark side- the part of an object opposite the light source
  
• reflected light- subtle light bouncing back into the shadow
• core shadow- the darkest part of a shadow sandwiched between the light side and reflected light
• value gradation-  The slow transition from one shade to another.

I've started below with a scanned pencil drawing, and used Photoshop to "paint" in the sphere in gray-scale.

Step one is the sketch. This step outlines the basic elements of the painting. It tells us were the objects are going to be placed in relation to each other. Here I've also used a line to indicate the shadow created by the sphere and a rough division between the light and shadow side of the ball. None of these lines will be visible by the end.

Step Two: I've simply added a middle gray overlay to my drawing. Starting from a middle-tone is preferable to starting on a white surface when painting. That way you won't have a lot of white to cover over. You simply push towards your darks and push toward your lights starting from the middle.

Step Three: I've filled in the shadow shape. Notice how the shapes are connected without regard to the edge of the object or the background. There is a dark shape and there is a lighter shape.

Step Four: Create a gradation from the shadow side into the light side. This transition should be soft because a rounded sphere transitions slowly out of the light. Already you can see some convincing form.

Step 5: Darken the "core" shadow and deepest parts of the cast shadow. Completing this step also creates the illusion of reflected light on the base of of the sphere.

Step 6: Paint in the light-side. Remember to preserve the "middle value" as part of the slow gradation to the light side. The lightest part should be the part closest to the light source (the upper left). I've also done this across the ground plane. Here I've used a white brush set to about 15% opacity. REMEMBER: Don't let you're gradation go all the way to pure white, otherwise your highlight won't show up.  Instead stop at about 15-25% gray.

Step 6: Create simple background gradation from the left to the right. Even on a flat one-toned surface there is always some color and/or value shift. Start looking for it.

Step 8: Add the highlight. This is just a touch of white to mimic the reflection of the light source on the smooth surface of the ball.  THAT'S it, you've just created a gray-scale "painting" of a sphere!

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COLOR:  Just for fun I created I placed a color overlay.  This won't create accurate color, but will help you start thinking about color.

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EDGES: Primarily painting is designing and organizing colored shapes. To do this convincing you must also give careful consideration to how soft or hard the edge between the colored shapes appear.  Look at the list below and try to identify these conditions in the pictures above and in your own drawings:

• A cast shadow has a hard edge.
• A form shadow has a gradating soft edge.
• Shapes in the distance have softened edges like they are out of focus.
• Use a hard edge when one form is overlapping another
• When the value of a foreground element overlaps a background element of the same value don't be afraid to "lose the edge" and letting the contrast disappear

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WHAT DOES THIS HAVE TO DO WITH DRAWING?

LINES VS. EDGES: Lines and Edges serve the same function.  In a drawing outlines play the part of edges.  They can also suggest the three dimensional shape of an object when adding shading that wraps around the form like a wire frame.

Thicker outlines are reserved for the larger forms while thinner lines are reserved for hatching, shading and smaller internal details. Also, items in the distance will have a thinner line or even a broken line to signify less contrast caused by atmospheric effects.

Cast shadows, like the chin's shadow on the neck or the shadow underneath the nose and eyes have a sharp edge. Form shadows "wrap around" the forehead and cheeks and have a softer transition when moving from the dark side to the light side.

In this drawing (above)  you can see how a 2D shape at left can become 3D form at right by following some simple rules.