Colour Temperature (1/2)

Why is colour temperature awareness important in the AV industry? Whether it's setting white balance for iPhone 4 or Nikon D90, your camera needs a starting point.

You've probably heard the phrase, "painting with light". How about the terms "red hot" and "white hot"? These and many other phrases refer to the use of colour temperature in still photography and cinematography.

The colour temperature setting in your video camera tells it how it should see white. Once properly adjusted, the camera sees the colour white as white and then adjusts for all the other colours accordingly. White balancing is a step that should never be overlooked or misunderstood, because white balance affects not only the proper visualization of objects and events in a scene - for instance proper skin tone - but it can also help to determine the overall mood of how a scene plays out within the frame.

Most video cameras on the market today have spot-on auto white balance control. However, as a director of photography, I can't remember the last time I used the auto white balance function on any of the video cameras I regularly use. I'm a big fan of using the camcorder's manual controls in nearly every situation, especially when it comes to controlling the colour temperature of a particular scene. I shoot a lot of medical scenarios like mock emergencies, simulated life flights, and even surgeries. I find that through the simple understanding of colour temperature and manipulation of that colour temperature in the camera's settings, I can successfully guide the viewer's eye and even their emotions while watching that scene.


Colour and Temperature

Colour and colour temperature can be crucial components of just about any scene. The lighting of an orange sky typically associated with a sunset in the desert not only serves as a distinct tone in the frame but also delivers information such as time of day while also delivering a feeling or mood.

It's important to remember that changes in colour temperature as seen by your camera are not necessarily seen the same way by the human eye. To understand colour temperature and ultimately how to control it, it's helpful to know a bit of simple physics. The colour temperature scale is derived from a theoretical "black body" known as a Planckian locus or Planckian radiator (a metal object having no natural colour of its own). When heated to incandescence (the giving off of light from a hot body due to its temperature), the metal body glows at different colours depending on its temperature, which is registered by degrees on the Kelvin scale (K). This is, of course, where the terms "red hot" and "white hot" derive.




Written by Michael Fitzer