Sources of Light

James Gurney: Pages 28-29

Direct Sunlight

• A clear sunny day has three different systems of illumination:
• the sun
• the sky
• reflected light
• Compared to sunlight, skylight is a diffuse, soft light.
• if the air is especially clear, the sky is even more blue-violet than usual and the shadows are darker
• more clouds = gray shadows
• The color of the ground and nearby objects reflect onto the shadow areas. 

Overcast Light

• Artists and photographers often prefer the soft illumination of a cloud-covered sky.
• ideal for complicated outdoor scenes
• allows one to paint forms in their true colors
• the stability of light allows artists to work without the light changing too much
• The layer of clouds diffuse the sunlight, eliminating the extreme contrasts of light and shadow.
• Colors appear brighter and purer
• The sky is often the lightest note in the composition

Window Light

• This light is popular with artists because of its constancy and its simplifying effect
• The daylight that enters a room from outside is usually bluish. 
• the cool color contrasts with the orange color of artificial lights in the room. 

Candlelight and Firelight

• All yellow-orange in color
• In firelit environments, smoke often scatters the light
• They often have a glowing appearance, with plenty of soft edges
• Fall off:
• the weakening of light
• Inverse square law; the effect of a light shining on a surface weakens at a rate comparable to the square of the distance between source and surface

James Gurney

Indoor Electric Light

• Most common indoor lights are incandescent and fluorescent
• Keep in mind: relative brightness, hardness/softness, color cast
• A hard light comes from a small sharp point (the sun or a spotlight)
• more directional and dramatic
• crisper shadows, brings out more surface texture and highlights
• A soft light comes from a wider area
• more flattering
• reduces confusion of cast shadows
• tonal transitions are more gradual
• Color Cast;
• dominant wavelength of a light source
• Regular incandescent lights are strongest in red and orange wavelengths and tend to be weak in blue
• Standard fluorescents emphasize yellow-green
• made to give the most light in the wavelengths to which the human eye is sensitive

Streetlights and Night Conditions

• In the past, there were two colors of light at night; moonlight and flame-based light. As electric lighting developed, new colors entered the nightscape. 
• Tips to learn about night illumination:
• take photos with a digital camera set on its night setting
• disable the white balance setting and photograph a color wheel under different streetlights
• try urban night painting (use an LED light to illuminate your palette)
• start a scrap pile showing modern cityscapes at night

Luminescence

• Incandescence; when hot/flaming objects give off light
• Luminescence; living and nonliving things that glow at cool temperatures
• Bioluminescence; organisms that can produce light
• Fluorescence; light that is produced by an object that converts electromagnetic energy into visible wavelengths
• Tips:
• Luminescent colors often gradate from one hue to another
• blue-green colors are the most common
• paint the scene in darker tones first, then add the glowing effects last

Hidden Light Sources

• 3 ways to light a scene;
• a source shining from outside the picture
• light inside the picture you can easily see
• light inside the scene that is concealed from view
• Leads mystery; viewer is intrigued to explore further to find out where the light is coming from