Understanding light

On Day 2, we had a demo by Tim. He talked about light.

light, variety, unity

How to determine direction of light? Identify the two points which form the

non-parallel forms - curvature around them

beautiful
gradeur

the light that shine forth from that which is well made
corelation between visual and physical

light the subject, object and means of drawing and painting

sphere is perfect and pure object

ideal form

the light is perpendicular to the plane that cuts through the sphere to form the shadow side i.e. the plane thru A and B in diagram










1.Direct light
Value - how light or dark is it
determined by orientation - planar position relative to light direction

2. Gradation - Planar progression expressed visually as values

In the sphere, top planes is plan most facing the light. It is the brightest and gets darker as it moves down to shadow shape.

Proximity - Amount of light that  can reach the surface
Orientation

Contrast - diff between lightest and darkest value on form
Reflected light

In poster study we are looking for 4 averages
1. shadows edge(tangent to light direction
2. reflected light
3. lighter light
4. dark light

gradation of light side and gradation of shadow side

An abstract representation of posterizing

posterizing at the level of the envelope

An arc hsa a single highpoint diving into two parts x. this is not natural form.

Natural form twist irregularly as we turn irregularly. asymmetrical curves

The demo continued on last day.

visual realization of volume of body.

Light and form are synonymous to the painter.

Block-in is ability to see constellation of points on the planes that define form.

to determine Angle(vector that can move in all directions 3 dimensionally) and Action

Planes cannot form right angles or cylindrical or square. No ideal geometry

This has been stressed again and again. Natural forms are highly irregular - Non-parallel and non-repetative

vectors turn and twist and progress in varying ways

variety and unity

a planar representation of shape of contour

sense of contour/sense of form

shadow's edge is also irregular and composed of planes which all have different angles and lengths, they live on an average vector thru space

core shadow -wherever reflected light is weakest. It is not like a belt. It can vary based on the reflector. Poster study is identifying 4 averages and see how they relate to each other. Highlight plane is separate from those 4 averages. 

Highlight plane is determined by light direction, viewer sight line and planar surface of form. It lies at one half angle produced by sight line and angle of light. 

If angle of sight line and direction of light is less than 90, highlight moves into light plane. it is ~ 90, highlight is on edge of dark light and light light

Highlight is dim mirror image of light source (windows in our case). If surface is pure matte, may not see highlight. Depends on texture and reflectivity of the object. Hair and fingernails are highly reflective in the body.

Simultaneous contrast/Field effect/foreshortened effects

Field effect - produces value changes. It is about the way we percieve depth/ foreground and background. Progression of gradations. It is more to do with perception than actual physicality. It is like a halo effect, slightly darker background along the edge of the figure. Field effect is changing at a steady rate. It is darkest where the ball is brightest. On shadow side opposite happens. Background is lightest where ball is darkest.

Foreshortened effect

As a plane is turning away from us, it is getting darker. It is not a value changes but an illusion of value change. There is change in color temp and chroma... not value.

light is subject, object and means of what we can express using color. Drawing comprises 87.5% of painting - Ingres.