Nothing Comes between Me and My Kelvins: Thoughts on Colour Temperature

White-balancing for daylight (left) and tungsten/incandescent (right) for a donut lit under tungsten/incandescent light.  Mmm….

In the Year 2 context lecture today we looked at colour theory, which included a discussion on colour temperature. Some students were particularly intrigued by the fact that the colour temperature of daylight is around 5500 – 5600K, which gives it a blue tone, while incandescent/tungsten light is between 2700 – 3200K, which gives it a red tone.


As I promised the students, here is a video that demonstrates the difference. Start it at 1:20 to see the really relevant parts. At the 2:00 mark Kris provides a demonstration of how daylight registers (super blue!) on a digital camera white-balanced for tungsten, and an immediate shift to how tungsten registers (super orange!) in tungsten white-balance:
CINEMATIC LIGHTING: Understanding Daylight vs Tungsten (Krisco Art Productions)
For interest’s sake, fluorescent light registers green on both (but especially on tungsten white balance).
All of the above is also true for film, although instead of white-balancing, which you can only do in digital photography, you just use film stock that is either balanced for tungsten or for daylight.
It even works when you’re shooting on black and white film (or in black and white).  No, really!  If you’re shooting a beautiful blue, mostly-sunny sky and you want to enhance the puffy white clouds that fill some of the space, pop on/in an orange filter and that will do the trick.  See?
Thinking so much about all of this made me yearn to shoot something on film again.  I love the complexity of loading the camera in the pitch-dark (or a change-tent that gets unbearably sweaty in seconds), choosing the right lights and setting them up, using the right gels or spun with the right stop-reduction to achieve the right colour and exposure, the precision of measuring the exposure using an old-school Sekonic… It’s both an art and a science — my two favourite things!
As computer-based animators, the NTU Animation BA students don’t need to go through any of this practical to-do, which could be a bit of a loss for some, but is definitely a huge gain for all.  Particularly in 3D software, you can adjust the lighting intensity and position as well as colour temperatures instantaneously and incrementally, which enables you to experiment with all kinds of contrasts, complements, and recreations until you find exactly the right one to fit your vision.  But even if we don’t have to physically apply our own colour filters, thinking about gelling and how it helps to create or recreate certain lighting conditions, moods and associations will be super useful for one’s animation practice.
As we’ll learn in next week’s context lecture, lighting can be a significant conventional factor of genre.  Can’t wait!