Saturday, March 5, 2011

Basic Planes

By simplifying form into planes, it becomes easier to understand and see how light affects form. There are four basic planes: front or upright plane, side(edge) plane, top plane, and under plane.

Top planes in the light
Always go 1 value higher than average 
More neutral than the average
Picks up the hue of the light source (e.g. in north light would shift towards blue)
Use hard edges

Under-planes in the light -
1 half value darker than average 
1 & 1/2 value darker than the top plane
Soft edges
Avoid going too dark

Top planes in the shadow 
1/2 lighter than average in the shadow
Soft edges
Can be more neutral

Under-planes in the shadow 
One half value darker that the average in the shadow
Can be illuminated by reflected light resulting in hue, value and chroma changes
No hard edges, edges  are soft all over

It is the angle that the plane presents to the light source that determines its value.

Translate the idea of planes back into painting form.

The Edge Plane:
The front plane is usually more chromatic than the side plane, especially with skin. The edge plane drops slightly in value and chroma as it bends away from view, due to the texture of the skin containing pores and hair follicles. This can be exaggerated when necessary. A shiny surface might produce a different result, where reflected light might increase the chroma.

© John Ennis 2011

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