Theory of Light and Shade pt. 2


By Sheri Doty

 

THE LIGHT SIDE IN TWO PARTS

Highlight

The lightest spot or streak is where the
light strikes the subject in exactly the
middle of the light side between the
shadow edge and the edge of the
object. A highlight can be shiny and
crisp on a glass or metallic surface, or
fuzzy and muted on a dull or textured
surface.

 

Light middle tones

Note, to avoid confusion, “always”
keep the values on the light side lighter
than the values on the dark side. In
reverse, the values on the dark side
are darker than the values on the light

side. It’s the middle tones on either
side that confuse the artist’s eye in
value relationships.

 

The Dark Side in Three Parts

Form Shadow in Three Parts

“Shadow edge” or “core shadow”

The edge where the light is blocked from the light source is the darkest value on the dark side. The core or darkest value blends into the middle tones from the
shadow edge on round subjects.

Dark middle tone

The variable values blended form the shadow edge on the dark side. Again, the dark middle tones are darker than any values on the light side. The human eye can trick the brain into believing the

lightest values on the dark side are the same as the darkest values on the light side. If the artist is confused about lights and darks, the rendering is less understandable.

CAST SHADOWS IN THREE PARTS

The vocabulary used to describe cast shadows in art come from shadow descriptions in astronomy. The umbra, penumbra and antumbra are the three distinct names given to the description of shadows cast by heavenly bodies. The umbra is the darkest part of a shadow considered the absence of light. The penumbra is a lighter outer shadow where the object is only partially obscuring the light. The antumbra is more obscure. When it is visible it seems to extend out from the penumbra in a lighter and less distinct way.