Beginners’ guide to colour temperature and white balancing
Posted on December 5, 2008
Filed Under Photography lessons
Our brain perceives colours the way we want it to; not the way it actually is. No matter what source – sunlight, fluorescent light or any other light – this quality of our brain helps us to see a colour alike under all lights, even though the different sources of lights render the same colour differently.
But the technologies used in photography are not advanced enough to give this quality to cameras. Read on to understand more about the different properties of colours and ways tackle issues related to colour balance.
What is colour temperature?
The electromagnetic spectrum contains all light frequencies from infrared to ultraviolet, and the visible light comes in the middle. As we move to the visible spectrum from infrared, the first light on the horizon is red, which has a very warm colour as well as a long frequency, and the last colour is violet, the coolest of colours and the light with the shortest wavelength.
Colour temperature is a simplified way to characterize the spectral properties of a light source and is measured in Kelvin (K). When the colour temperature is low, the light will be warm i.e. more yellow or red. Similarly, when the colour temperature is high, the light will be cool, meaning more bluish.(means more yellow/red).
For example, the colour temperature of candlelight is 2000K (approx) while that of the moonlight is 4100 K. A typical daylight or an electronic flash light has a colour temperature of 5500-6000 K while the light emitted by a normal CRT screen has a colour temperature of 9300 K.
Color temperature chart
1500 K Candlelight 2680 K 40 W incandescent lamp 3000 K 200 W incandescent lamp 3200 K Sunrise/sunset 3400 K Tungsten lamp 3400 K 1 hour from dusk/dawn 5000-4500 K Xenon lamp/light arc 5500 K Sunny daylight around noon 5500-5600 K Electronic photoflash 6500-7500 K Overcast sky 9000-12000 K Blue sky
Understand your white balance settings
By default, most of the digital cameras show real colours (as human eyes see) under flashlight or normal daylight. But, taking photos with available light is inevitable in certain occasions. For example, you are at a party and you want to take photographs at a room that is lit up by fluorescent light. If you prefer to use the available light instead of flashlight, you need to do white balancing.
As we learnt now, lights from different sources have different colour properties, and correcting the camera’s colour settings to match with the available light is called white balancing i.e. camera makes corrections to display white as whiter under available light.
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How does it affect your photographs?
Most cameras have an auto mode and it works fine with flash and outdoors. Problems start when you switch the camera to manual mode or shoot under mixed lighting – when the subject is lit up by more than one light source, like a combination of fluorescent light and daylight.
Suppose you have selected colour temperature as “indoor”, which is commonly shown with the symbol of a light bulb, and is taking indoor photos during daytime. You would have more than one main light sources i.e. the sun and the tungsten light. The resulting photos would probably be bluish.
Shooting subjects with excessive colours will also be a problem in Auto White Balancing (AWB) mode. For example, when you are photographing a kid with the background of a red wall under normal daylight, the camera does its own adjustments to reduce the impact of red by adding blue. You can then see that the photo has excessive blue cast.
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How to choose the right white balance manually?
The easiest way is to carry a large white paper with you and tell someone to stand near the subject with the paper. Then, point the lens towards the paper, standing at the spot where you would stand to take photo, and set white balance manually (custom white balancing). You may also ask a person wearing white dress to stand near the subject and make use of his/her dress instead of white paper.
Using a white balancing filter like Expodisc is an effective alternative to the above-mentioned method. Using this filter is pretty simple. Put the filter on your lens and stand at the same position where your subject is. Then point your camera towards the shooting point and set the white balancing. Then comeback to your original shooting position and click.
To get better at white balancing, spend some time on understanding more about the properties of lights from each sources and choose settings accordingly. Once you grasp the basics, keep experimenting under complex lighting conditions and compare the results. Happy balancing!
Also read
Improve your landscape pictures with HDR photography
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Incandescent light bulbs will soon be phased out because they waste a lot of energy.’**