Anatomy Of Light On Angular Shapes 

In the real world, light falls on every object around us illuminating some portions and throwing other portions into shadow.  This lesson explores how the effect works on angular forms.

Using The Medium To Simulate Complexity

Light effects are complex and create complex patterns of light and shadow. No matter the quality and effect, there are distinct light, middle and dark values that are recognizeable. In most cases, these separate areas of light and shadow have variations and gradations resulting in ranges of value.

Watercolor is an excellent medium for re-creating this effect. The action of the medium – water – naturally creates variations in wet, fluid washes. This lesson takes advantage of this quality in showing how to recreate subtle light patterns with the help of the medium.

Understanding Value Patterns

This painting lesson steps through the process of creating the pattern of light and shadow on simple cubes.  Unlike rounded objects, like spheres, the value shapes on angluar objects like these are separated from others with distinct, angled edges.

Simple Shapes

Another important aspect of this lesson is the idea of simple shapes.  Simple shapes, like the cubes in this lesson, are the underlying form and structure of more complex objects.

It doesn’t take a lot of imagination to see the simple structure of a building, box, paper bag, chair, piano, table and many other objects in the form of a cube.

This lesson shows how to re-produce the effect of light on a 3D angular object. Although it is simplified in this lesson, the same ideas apply to any object that is basically and angular, cubical object.  Once you’ve learned how to create the effect of light on a simple cube, it is easy to translate the ideas to more complex and realistic objects.


These are the identifiable parts of the Anatomy of Light and the words used to describe them. These areas are the same on all object, rounded or angular.

Anatomy Of Light Definitions

Form Light – the area of the surface that is receiving direct light. The  highlight, center light and halftone are all found in the Form Light

Highlight – this is usually a small ‘spot’ of that is a reflection of the light source. The highlight is  the lightest value within the  Form Light. The highlight may  be more or less distinct, or not apparent at all, depending on the reflective character of the object

Center Light – this is the part of the surface that is receiving the most direct light and is the lightest value – except for the highlight – in the Form Light

Halftone – this area is least amount of direct light and has darker value than the Center Light.

Terminator – the edge that marks the boundary between Form Light and Form Shadow. This is often appears to be a soft edge, since the shift from Form Light to Form Shadow is gradual.

Form Shadow– the area of the surface that is turned away from the light. It can be referred to as ‘Shade’.  It includes the shadow core, and reflected (or bounced) light. This area has values that are darker than any in the Form Light.

Reflected Light – this is the lightest area of the Form Shadow and is so because some light rays are bouncing from objects and surfaces back into the Form Shadow. Reflected light is seen near the bottom and back edges of the object.

Shadow Core – this is the darkest area of the Form Shadow. It usually appears near the Terminator because there is not enough reflected light to lighten the entire Form Shadow

Cast Shadow– the area on the surfaces around the object that have direct light blocked at the Terminator. This area usually has the darkest values in the scene.  It includes the occlusion shadow.

Occlussion Shadow – this is darkest area of the Cast Shadow and usually occurs where two objects or surfaces meet and join.

What you’ll need

  • Brushes – a single medium round
  • Colors – a dark neutral:  Ivory or Lamp Black, Sepia, Neutral Tint, or even Paynes Gray
  • Watercolor paper – preferably Arches 140lb Cold Press cut to about 7″ x 11″ or so

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Related Lessons

Anatomy Of Light On Round Shapes

a sphere painted in watercolor with form light, form shadow, and cast shadowThe effect of light on a scene can be  very complex. The effect can range from subtle to dramatic. No matter the quality and effect, there is a distinct pattern of light, middle and dark value that is recognizeable.

This painting lesson steps through the process of creating the pattern of light and shadow on a simple round shape.  We’ll create each area of light and shadow, using only ranges of value and explain how each area differs from the others.

The lesson also covers the vocabulary that helps organize our thinking and identification of light and shadow.

Value Study For A Simple Scene

Even the simplest of scenes has many different values, often differentiated from others in subtle ways. 

The lesson above breaks down the Anatomy Of Light as it appears on angular forms. In this lesson, you’ll learn how to create a simple structure of no more than a small handful of large shapes filled with one of three values.

The process respects but simplifies areas of light and shadow, while creating a strong structural Value Composition. The lesson shows how to work from a photo of a simple scene – converting the actual, complex values created by the effect of light, into three simple values.  

As in the lesson above,  we’ll let the action of medium create some of the subtle gradations that occur in any area of light or shadow. 

The Graded Wash

watercolor graded wash - a basic watercolor painting techniqueThe Graded Wash should be an essential part of your watercolor painting repetroie.  

It is used everywhere in the Anatomy Of Light Sphere painting, and Pomegranate painting exercises above. 

These washes create beautiful and expressive passages in your painting. Even better, they are without peer when it comes to representing the subtle effects of shifting light that occur all around us in the natural world.

Learn To See And Paint Light And Form Learning Track

Recreating the effect of real world light on objects in a painting means creating the changes in color and value that simulate the real-world effect.

Although the effect of light has many, sometimes unexpected, visual impacts – there are certain, tried and true ways of creating patterns of light and shadow in our paintings. In turn, these patterns will seem to reveal form through the illusion of three-dimensions.

This Learning Track includes twenty lessons for understanding and showing the effect of light in paintings. The lessons start with basic ideas and use them to paint more and more complex scenes and subjects.