The Colour of Light

This next section on light deals with colour temperature. 

Light at different times of the day and under different conditions will have different colours. Our eyes are so highly developed that we do not see this change, our brain quickly adapts to the difference, but digital sensors, fitted in modern DSLR's cannot adapt. 

Colour temperature is expressed in Kelvin scale. I wont go too deeply in the science of colour temperature, but I will give a quick overview. 

Lets start with daylight, the temperature of the shade on a sunny day around midday is around 5500k, however if clouds start to obscure the sun, the colour temperature will go up to 6000-7000k, quite a lot bluer. As you can see in the chart below. 

During sunrise and sunset times, the temperature is much cooler, which is ironically warmer in look, i.e reddish yellow. 

How does this affect photography?

A photograph taken will record the temperature of the light as a hue across the overall colour balance and can often take an unpleasant cast from poor lightning conditions, i.e. incandescent bulbs and candles give a very warm light giving a strong orange cast across a photograph that can often lead to unflattering and unnatural tones. 

On digital cameras colour temperature is controlled by choosing a setting with the cameras menu, the WB option, specific to the environment in which you are taking the photograph. Cameras can be set to Tungsten, cloud, shade etc. Or alternatively they can be set to Auto White Balance (AWB) However using AWB, as with all auto settings on your camera can lead to disappointing results. 

Therefore a good understanding and appreciation of colour temperature prior to taking the photograph will produce far more pleasing results.

Further control of colour temperature can be achieved using editing software, such as Adobe Lightroom, or Photoshop if the initial photograph was taken in RAW. If you remember taking photographs in the RAW setting means that all the information is captured at the time of taking and can be edited later. 

However relying on post possessing to correct faults with the colour temperature, usually means the photograph was taken incorrectly to begin with!