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Color Temperature

Color Temperature

By L. Ron Hubbard

The measurement of color temperature was originally calculated by heating a piece of black carbon until it radiated the various colors of the spectrum and then measuring the temperature of the carbon at those colors. Simply stated, this means that when an object is heated to an appropriate temperature, some of its radiated energy is visible. When metal is gradually heated, the first visible color is “dull cherry red.” As the temperature is raised, it visually becomes “orange” and then “yellow” and finally “white” hot. These measurements are known as degrees Kelvin, named for English physicist Lord Kelvin (1824–1907), who devised the scale. (The Kelvin temperatures are the same as Celsius, except the Kelvin scale starts at “absolute zero,” the hypothetical temperature at which all molecular activity ceases: -273.16° Celsius.) By way of example, afternoon daylight typically measures 5500° Kelvin, meaning a piece of black carbon heated at 5227° Celsius emits the same light spectrum as that of daylight. Also tungsten light (indoor photoflood lamps) typically measures at 3200° Kelvin.

Color Temperature of Artificial Light
Match flame 1700K
Candle flame 1850K
Tungsten lamps
40–100W 2650–2900K
200–500W 2980K
1000W 2990K
Color Temperature of Daylight Light
Sunlight:
Sunrise or sunset 2000K
One hour after sunrise 3500K
Early morning, late afternoon 4300K
Average noon (Washington, DC) 5400K
Midsummer 5800K
Overcast sky 6000K
Average summer daylight 6500K
Light summer shade 7100K
Average summer shade 8000K
Partly cloudy sky 8000–10000K
(K = Kelvin)

Portrait of a Caribbean Minister

Portrait of a Caribbean Minister

By L. Ron Hubbard

The Curaçao Bridge

The Curaçao Bridge

By L. Ron Hubbard

On Behalf of the New York Explorers Club

On Behalf of the New York Explorers Club

By L. Ron Hubbard

The Synagogue of Mikvé Israel–Emanuel

The Synagogue of Mikvé Israel–Emanuel

By L. Ron Hubbard

The Lisbon Maritime Museum

The Lisbon Maritime Museum

By L. Ron Hubbard

Cameras of the Photo Shoot Organization

Cameras of the Photo Shoot Organization

By L. Ron Hubbard

Mamiya C33

Mamiya C33

By L. Ron Hubbard

The Gandolfi

The Gandolfi

By L. Ron Hubbard

The Rollei 35

The Rollei 35

By L. Ron Hubbard

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