Absolute Beginner's Guide to Digital Photography

The color temperature of “white light” is measured on the Kelvin scale (see Figure

5.1). Warm colors of light have low color temperatures; cool colors of light have high

color temperatures.

CHAPTER 5 EXPOSURE AND FOCUS 65

FIGURE 5.1
The Kelvin scale
measures color
“temperature.”

20,000 K

10,000 K

5,000 K

2,500 K

1,600 K

5500K daylight type film

3400K Type A film (photoflood bulb)

32000K Type B film (Tungston film)

Blue north sky

Overcast sky

Electronic flash

Noon sunlight

Afternoon sunlight

Photoflood bulbs

Quartz halogen lamps

100 watt bulbs

Candlelight fireworks

Different color films are manufactured for different color temperatures. Daylight film

is balanced for 5,600° Kelvin (or K) light and gives accurate color with midday sun-

light or electronic flash. Indoor film, called Type B or tungsten film, is balanced for

3,200°K light and gives excellent color with professional quartz-halogen lights (pow-

erful lights up to 1,000 watts). It will give acceptable, slightly warm color with ordi-

nary incandescent light bulbs, which are 2,500°K to 2,800°K.

Video cameras and some digital cameras have circuitry to automatically adjust the

color balance to match the color of the light source. Digital cameras also provide set-

tings that enable you to emulate the warm yellow cast of indoor lighting or the

harsh green color common with fluorescent lights. These custom settings resemble

different types of film such as tungsten and indoor film.