Many cameras allow us to dial in a specific colour temperature for a shot, rather than manually set it with a white or grey card. It sounds good, but can deliver alarming results.

Consider these two images shot under different lighting systems. In both cases, I’ve put a daylight Dedo DLED-4 over the shoulder as a sort of 3/4-backlight-kicker thing. It’s a look I like. That’s a fixed constant. I like to light to 4500 ºK which gives me wriggle room over colour temperature, and is a piece of cake with a bi-colour device like the Dedo Felloni. I had to shift the camera to 5600 to match the lighting sources with my cheaper LED panel lamps.

The camera was a Sony PMW F3 with Nikkor 35-70 at around f4.

Immediately, you can see that the Non-brand LED panels are green. Not just a little, green, they are Incredible Hulk Green. Note the daylight highlight on Rick’s temple – its about the same in both images, though I did use 5600 ºK on the F3 for the Non-brand LEDs. I tried using half CTO, but the results were absolutely hideous.

Both images are from LED sources and are untouched in terms of grading. The Fellonis are neutral, accurate and appear to all intents and purposes to be full spectrum. I also find the diffusion and fill tweaks to be particularly nice, considering the cramped location and speed at which we had to work.

So it’s plain: be careful of setting a colour temperature in-camera – it works well with continuous spectrum lighting, but looks horrible if you use more restrictive sources – especially LED devices from the lower end of our budget. They output a very restrictive light.

But that’s not the whole story.

Let’s do what we’re supposed to do: let’s white-set on a known white reference (not just a bit of photocopier paper). Let’s re-light with our non-brand LED panels. At first glance, hey! It looks good!

Let’s compare with the more ‘continuous spectrum’ Fellonis on the right. Note that Rick’s skin tone on the left is far flatter with a hint of grey and yellow. Note also that the pure daylight source behind him is now casting a MAGENTA light over his hair and shirt – all that green has been neutralised, leaving a nasty Magenta odour hanging about. If we try and cancel that out, it will bring the green back in. Meanwhile, the brighter reds and oranges have been tempered by removing so much green.

The result? There’s an ashen look to the skin. It’s a bit dull. It lacks life. On the right, there’s some flush to the face around and under the eyes. The backlight and his shirt pick up the fresh daylight from the three-quarter back. It’s natural, rather than made up.

But bear in mind that if I were using the Non-brand LEDs in a mixed environment, trying to blend them with existing daylight or tungsten or – egad, even worse – both, the results are just awful. That green tinge is back, and it really doesn’t sit with anything else. I remember vividly a shoot trying to use these No-name panels in a mixed lighting situation, pinning half-CTO and diff over them to try and calm them, and still seeing the green tinge seep through.

• Take home 1: be careful using pre-set Kelvin settings as not all lighting is full spectrum. You’re choosing a compromise. It can be the best decision, but it can also be wrong.
• Take home 2: a proper white-set is the way to go in difficult situations, but strong corrections will impact other lighting sources (ambient, backlight, fill, etc)
• Take home 3: Unless shooting raw, correcting for White Balance issues can only take away data from your image and reduce its quality.

Note: look out for the full story (and more) on moviemachine.tv soon.