The document discusses light and shadows in three sections. It introduces the concept of light logic and how light interacts with objects to create the illusion of volume. It describes how value scales are used to depict different tones from light to dark using chiaroscuro techniques. Finally, it explains how shadows are formed when light hits an object, distinguishing between light sides, form shadows, cast shadows, and different shadow zones like the umbra and penumbra.

1. UNIT 3
LIGHT AND
ITS SHADOWS

2. UNIT 3 - LIGHT AND ITS SHADOWS
3.1 - THE ILLUSION OF VOLUME
To create the illusion of space, depth and volume on a two
dimensional surface we use different methods to trick the
viewer, like overlapping, transparency, and other applica-
tions of spatial proportion.
But there is another method to create space and volume which is more realistic and effective using
what we called “Light Logic”. Light Logic refers to how light interacts with objects.

3. UNIT 3 - LIGHT AND ITS SHADOWS
To describe the different tones that go from light to dark we use the term value, which describes all
neutral tones from white, black and all the gray tones in between. If we put all these tones in order
we get what we call value scale.
One of the most used and useful applications of value is creating the illusion of volume and mass on
a two dimensional surface by using the technique called Chiaroscuro.The word Chiaroscuro is a
combination of two Italian words that mean light and dark (chiaro (clear, light) + oscuro (obscure,
dark).

4. UNIT 3 - LIGHT AND ITS SHADOWS
3.2 - A LIGHT SOURCE AND SHADOWS
When a light is projected onto an object or figure we dis-
tinguish three different parts: a light side and two diffe-
rent shadows whic are a cast shadow and a form shadow.
LIGHT SIDE:
We find two different zones:
Highlight
The lightest spot or streak is where the light strikes the
subject in exactly the middle of the light side.
Light middle tones (halftones)
The middle tones on the light side which are lighter than
the values on the dark side.

5. UNIT 3 - LIGHT AND ITS SHADOWS
FORM SHADOW
We find three different zones:
“Shadow edge” or“core shadow”
It is the darkest value on the dark side.
Dark middle tone
The variable values blended form the shadow edge on the
dark side.
Reflected light
If the object being is sitting on a white table, the light from
the table reflects back onto the object and makes the
shadow side lighter.

6. UNIT 3 - LIGHT AND ITS SHADOWS
CAST SHADOW
When the source of light is blocked by an object it casts a shadow. The length and shape of the cast
shadow depends on the placement of the light source.

7. UNIT 3 - LIGHT AND ITS SHADOWS
The umbra is the darkest part of a shadow considered the absence of light. The penumbra is a ligh-
ter outer shadow where the object is only partially obscuring the light. The antumbra seems to
extend out from the penumbra in a lighter and less distinct way.

8. UNIT 3 - LIGHT AND ITS SHADOWS