Back when I started using flash to shoot Roller Derby (in an attempt to get sharper blocker shots for GRG bout programme covers) I had huge colour balance problems.
A quick colour 101 for non-photographers. Colour is said to have a temperature, because it’s defined as the colour that would be produced if an ideal black-body radiator is heated to that temperature. Heat a piece of iron to 900 Celsius and it’ll glow red hot. Heat it to 5778 Kelvin (5504 C) and, assuming it hasn’t vaporised, it’ll glow the colour of the sun. 5778 K is really hot. Digital cameras expect daylight to be 6500 K. Confusingly, what we refer to as warmer light (more orange) is produced by cooler temperatures.
So the problem is that usually the hall lights are warmer (more orange) than the flashes, so the closer a skater is to a flash the colder (bluer) the light on her will appear. At worst, skaters close to a flash will be lit with more cold light, and at the same time skaters further from the flash will be lit with more warm light, so it’s impossible to get everything the same colour when editing. As well as making the editing much more complex this annoys me more than a little.
Now I know that most people probably wouldn’t notice as what they’re looking at is the gameplay in the image, but I’m a photographer. We worry about these things. And as anyone who had a good giggle and my reaction to them opening the Berlin Arena skylight in the middle of a game will tell you, I’m kinda picky about colour calibration.
The solution is to add colour correcting gel filters to the flashes, and these are readily available in different strengths – most commonly full CTO (convert to orange), ½ CTO and ¼ CTO. The problem is trying to figure out which filter, or combination of filters is needed for an unfamiliar hall. It’s difficult to eyeball this as your eye tends to compensate for the colour of the ambient light, and after a while you just stop seeing it. Then you look at a correctly balanced image on a camera screen and it looks too blue.
Read more ›