Color and Light - Surfaces and Effects Chapter 9
SURFACES AND EFFECTS
Transmitted Light
Transmitted light is light that either bounces off a slightly transparent surface or goes through it. This light is rich in color when it travels through the surface and lacks color when it bounces off. Frequently this is seen in leaves - and there are many kinds of light that go through leaves.
James Gurney's Four Kinds of Light on Leaves
1. Transmitted Light - Very strong yellow green color
2. Leaf in shadow, facing down - darkest green.
3. Leaf in shadow, facing up - blue green, reflecting the sky.
4. Direct sunlight reflecting off the leaf - highest value, but low chroma. Lots of texture.
Look for these color groups in groups of foliage to create a realistic tree.
Subsurface Scattering
Subsurface scattering is light that is absorbed into an object and scattered around until it comes out the other side. Think of the orange peel and the toy cow. This kind of light is usually very well seen in translucent flesh, small objects, and when objects are backlit.
This also happens in human ears and nostrils, where the flesh is thin enough for light to come through.
Color Zones of the Face
On a light skinned face, subtle colors appear on the skin. The forehead is typically light gold, from the eyes to the nose is red, and from under the nose to the bottom of the chin is more grey/blue. These colors are very subtle and almost unnoticeable, and more perceptible in men.
The reason for the red color in the center of the face, and specifically in the nose, cheeks, and ears is because there is more blood being carried to those areas. Chronic alcohol drinkers often have ruptured capillaries, creating a more permanent reddish color, and exposure to the cold brings blood to the surface, emphasizing the same.
Specular Reflections
Any object that is shiny will reflect what is around it. Specular reflection is specifically when light bounces off its surface in the same direction that it came towards it. Diffuse reflection bounces off in all directions. Often reflections are a combination of both.
James Gurney's Three Rules of Specularity:
1. The more reflective the surface, the broader range of values you need to paint it. (it reflects more values)
2. Convex reflective surfaces reflect a miniature view of their environment and are very detailed.
3. Specular patterns go on top of traditional modeling factors such as value.
Highlights
Found on wet or shiny surfaces, the planes that reflect the light source back are called highlights. There are two different kinds of highlights.
Specular Highlights are help define form. Highlights on a glossy surface are not usually pure white, but a mix of the source light color and the color of the object.
Annular Highlights are circular highlights on metal or on tree twigs. The circle the highlights create on the twigs point to the location of the sun above. They can be found on cobwebs.
Color Corona
A color corona is an area of colorful light around a bright light source.
The sun is a source of bright light, as can be car headlights, streetlights, and highlights from the sun. Light spreads from the source and the surrounding objects take on the color of the light source.
Motion Blur
When objects are moving very quickly, there are two different kinds of blur that can apply with a still image; one is Motion Blur and the other is Speed Blur.
Motion Blur occurs when the "camera" or viewer is stationary and something is moving quickly past it.
Speed Blur is found when the "camera" or viewer tracks along with something moving at very high speed.
With both types, the faster an object is moving the more it is blurred. Often the blur will increase in the background with Motion Blur because the objects of focus are supposed to be crisp and obvious. With Speed Blur, objects blur from the vanishing point in the direction the object is moving. Only edges and shapes going along the path of movement will become blurred; everything else is in focus.
Photos vs. Observation
Photos do a poor job of documenting color, which can be captured by observation. Photos will darken shadows, lighten lights, and mesh colors to be more similar. Additional weak sources of light and color are often lost.
To document a scene for later, note color and take a picture to remember details.
Transmitted Light
Transmitted light is light that either bounces off a slightly transparent surface or goes through it. This light is rich in color when it travels through the surface and lacks color when it bounces off. Frequently this is seen in leaves - and there are many kinds of light that go through leaves.
James Gurney's Four Kinds of Light on Leaves
1. Transmitted Light - Very strong yellow green color
2. Leaf in shadow, facing down - darkest green.
3. Leaf in shadow, facing up - blue green, reflecting the sky.
4. Direct sunlight reflecting off the leaf - highest value, but low chroma. Lots of texture.
Look for these color groups in groups of foliage to create a realistic tree.
 |
| Michael James Smith |
Subsurface Scattering
Subsurface scattering is light that is absorbed into an object and scattered around until it comes out the other side. Think of the orange peel and the toy cow. This kind of light is usually very well seen in translucent flesh, small objects, and when objects are backlit.
 |
| Subsurface scattering of light in a hand. |
This also happens in human ears and nostrils, where the flesh is thin enough for light to come through.
Color Zones of the Face
On a light skinned face, subtle colors appear on the skin. The forehead is typically light gold, from the eyes to the nose is red, and from under the nose to the bottom of the chin is more grey/blue. These colors are very subtle and almost unnoticeable, and more perceptible in men.
 |
| JoAnn Jeff Hein Though it's exceptionally subtle, the face is divided into sections of different color. |
On men, if they have dark hair follicles their chin areas often get a grey cast. On women, as in the painting of Joann above, the area around the lips is carrying deoxygenated blood away from the area, creating a greenish tint.
The Hair Secret
"To avoid the stringy look, use big brushes, keep the masses simple, soften the edges, and control the highlights." James Gurney
Tips from James Gurney's book:
Focus on masses with hair.
Caustics
Caustics is the way that water and drinking glasses or vases focus light into lines or spots of specific light.
Different shapes can be created with different kinds of glasses or vases, depending on the curvature of the object. In the water, caustics often creates a series of wavy lines of light. They don't appear further than twenty or thirty feet into the water, on sunny days.
"To avoid the stringy look, use big brushes, keep the masses simple, soften the edges, and control the highlights." James Gurney
Tips from James Gurney's book:
- Group strands of hair into large masses
- If the edges where the hair meets the head are too strong, the hair will look like it is sitting on top.
- Visualize masses of hair as ribbons. Highlights go across, not along.
- When hair is short/pinned to head, highlight goes across the entire head. The whole head turns darker as it turns from the highlighted section.
- Use a large brush, state the largest masses, keep all forms simple without much detail
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| Lotti Louis Smith |
Caustics
Caustics is the way that water and drinking glasses or vases focus light into lines or spots of specific light.
 |
| Caustics - the way light is focused by water |
Reflections from caustic light can be cast upward from the water too.
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| Pinterest Water reflected onto the ceiling and walls. |
Specular Reflections
Any object that is shiny will reflect what is around it. Specular reflection is specifically when light bounces off its surface in the same direction that it came towards it. Diffuse reflection bounces off in all directions. Often reflections are a combination of both.
James Gurney's Three Rules of Specularity:
1. The more reflective the surface, the broader range of values you need to paint it. (it reflects more values)
2. Convex reflective surfaces reflect a miniature view of their environment and are very detailed.
3. Specular patterns go on top of traditional modeling factors such as value.
Highlights
Found on wet or shiny surfaces, the planes that reflect the light source back are called highlights. There are two different kinds of highlights.
Specular Highlights are help define form. Highlights on a glossy surface are not usually pure white, but a mix of the source light color and the color of the object.
Annular Highlights are circular highlights on metal or on tree twigs. The circle the highlights create on the twigs point to the location of the sun above. They can be found on cobwebs.
 |
| Devils Lake Fern Gully Wisconsin Woodland Found on Etsy Note the curvature of the highlights in the branches. |
Color Corona
A color corona is an area of colorful light around a bright light source.
 |
| Pinterest Example of a corona in a sunset. |
The sun is a source of bright light, as can be car headlights, streetlights, and highlights from the sun. Light spreads from the source and the surrounding objects take on the color of the light source.
Motion Blur
When objects are moving very quickly, there are two different kinds of blur that can apply with a still image; one is Motion Blur and the other is Speed Blur.
Motion Blur occurs when the "camera" or viewer is stationary and something is moving quickly past it.
Speed Blur is found when the "camera" or viewer tracks along with something moving at very high speed.
With both types, the faster an object is moving the more it is blurred. Often the blur will increase in the background with Motion Blur because the objects of focus are supposed to be crisp and obvious. With Speed Blur, objects blur from the vanishing point in the direction the object is moving. Only edges and shapes going along the path of movement will become blurred; everything else is in focus.
Photos vs. Observation
Photos do a poor job of documenting color, which can be captured by observation. Photos will darken shadows, lighten lights, and mesh colors to be more similar. Additional weak sources of light and color are often lost.
To document a scene for later, note color and take a picture to remember details.
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