Color Temperature

What is Color Temperature
How to Correct the color temperature
How to correct the color

What is Color Temperature

Color temperature doesn't related with the heat. The ratio of belueness or redness which white light leans is Color Temperature

Color temperature measures with Kelvin.
1Kelvin=1Celcius+273Celcius degree
Kelvin found by the man surnamed Kelvin by heating a metal called Black material.

This material changes color when heated and Kelvin measured the degrees of the colors. At the end of the experiment Kelvin found the most common degrees:

• 1700K-1900K........Match flame's light
• 1950K..............Candle Light
• 2100K..............Sun rise at very foggy weather
• 2700K..............Sun rise at normal weather
• 2900K..............Tungsten lamp(Edison lamp,home lamps)
• 3200K..............Tungsten halogen lamp
• 3500K..............1 hour after sun rise in normal weather (amateur projectors,shopwindow lightnings)
• 4500K..............Morning-evening sun light
• 5600K..............Photographic day light in typical natural conditions(High,partly cloudy,midday sun)
• 6500K..............Average sunny summer weather,blue sky
• 7500K..............Cloudy weather
• 8000K..............Very sunny weather(desert sun)
• 10000K+............Around the sun(very bright light)

Thats why we see our pictures in orange or blue tones...

How to Correct the color temperature

Basically we cant change the characteristic of the Sun light or the other natural lights. But we can use filters on the human-made lightning sources.

There are two main method to change the characteristic of the light.

1. CTO: Color Temperature Orange
2. CTB: Color Temperature Blue

By the way only the method of measuring the color temperature is to use e Kelvinmeter. Kelvinmeter measures the light and gives the values in Kelvin. However we have to know the MIRED value to chose the right filter for correction.

MIRED (Micro Reciprosal Degree)

Mired value used in the value changes of light source.

Example: Light source is giving 3200K, value to transform = 5600K

MIRED / CT filter equivalences:

In cameras, films and CCDs (Charge coupled device) are produce with the setting which is correct for 3200K. That means: if the color temperature of the environment is 3200K all the white colors will acquire right.

So we can say:

color temperature of the light source > color temperature of the camera
=> whites lean to blue

color temperature of the light source < color temperature of the camera
=> whites lean to orange

How to correct the color

Sometimes light sources leans to some basic colors except the color temperature

Example: fluorescent lamps leans to green.

Generally we see this kind of leans in the cold light sources.

To correct the color we use Color Correction filters. We use the opposite color of the leaning to correct. Here is the color scheme which shows the light mixtures:

We have 3 main and 3 secondary colors these are:
Main Colors: Red (R), Green(G), Blue(B)
Secondary Colors: Cyan (Cy), Magenta (Mg), Yellow(Ye)
We dont neet to produce the black because in the camera we already got the light-protected(black) room.

To produce white light:
R + G + B = W
R + Cy = W
G + Mg = W
B + Ye = W

To correct the color we use color correction filters according to the color density. However the correcton dims the light. Let's look at the table below and see how many f stops do the filters dim?

KODAK COLOR CORRECTION FILTERS

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From door/Nick (4) on August 7, 2005 12:54:13 AM CDT Where are all the pics? Reply

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