So first we begin by reading about form and analyzing lighting on spheres. There are two points of darkest shadow: the core of shadow and the occlusion shadow. Sunlight causes more contrast and a stronger terminator line. Overcast lighting causes a shadow to transition more gradually at the terminator. The terminator is the area where light shifts to shadow.
A tip in creating form is grouping colors into a few color planes, top planes (receive the most light), front planes (midtowns), and side planes (shadows).
Also when adding texture to form it tends to disappear into shadow areas.
A good example was a sketch of drapery.
Separation of Light and Shadow
The value of a color is the measure of its lightness or darkness in comparison to a scale of grays in between pure white and pure black. Sunlight can alter a black to appear more white than a white in shade.
Half Shadow
Half shadow creates drama like the conclusion of an epic day. A soft edge between the light and shadow suggest that something far away is casting the shadow. Colors shifted here going from the lit spots to the spots in shadow.
Occlusion Shadows
When two forms meet occlusion shadows occur for example when you press two fingers together there appears a dark line in between them. Occlusion shadows also appear when objects are close enough to one another to not allow light in.
Three-Quarter Lighting
This is the famous portrait painting lighting. This can be noticed in paintings where a shadow is cast from the the nose onto the cheek. There is usually a key light, that which causes the shadow to be made, and a fill light which affects the color of the shadow. It may cast a tint of green or red that effects the lighting. Short lighting occurs when the shadow of the nose falls to the shaded side of the face. This also called Rembrandt lighting.
Frontal Lighting
Frontal lighting is the when a light is shining directly on the subject from the artists view. A natural outline is created by this along with a more two-dimensional view instead of sculptural view.
Edge Lighting
Opposite of frontal lighting, edge lighting comes from behind placing the object(s) in shadow and creating an illuminating rim around the object. The rim light varies according to the size of the planes facing backward. It can occur outside when the sun is low in the sky. Highlights of light usually appear on a hard boney surface
Contre Jour
This type of lighting is the lighting that comes from behind an object so strongly that it sometimes melts away the edges of the form. Example:
Light from Below
I like the examples given of this light: flashlights or objects illuminating an evil face, a book illuminating sunlight on a woman face out at the beach or pool, or a spacecraft or plane lit from below. Tip: to make an aircraft, ocean liner, skyscraper will appear larger than they really are if lit only on a few parts from small, weak lighting from below.
Reflected Light
Personally I love finding and identifying reflected light. Gurney lists five truths about reflected light:
- In shadows, up facing plane are cool and down facing planes are warm.
- The farther you are from a source, the quicker the reflected light falls off.
- The effect is clearer if you remove other sources causing reflected or fill light.
- A shadow is the color is the sum of all the sources of reflected light and local color.
- Oh sunny days vertical surfaces or planes receive both warm light from the ground and cool sky light.
Spotlighting
Ambient light is light left over after the key light is removed. Spotlighting is mainly used in theater to show dramatic lighting on a subject to be focused on. In plays a blue light is shown from above and a red from below to highlight the spotlight.
Limitations of the Form
Clouds are a difficult subject when dealing with light. They, "transmit a greater quantity of light to the shadow side through internal scattering than the volume of light they pick up from secondary sources. Sometimes clouds or trees or so thin the light passes through, other times they are thick enough to have a light and shadow side. The neat thing Gurney points out is that this world is not composed of plaster, everything is made from, "a wide variety of materials and surfaces." (page 71)
