In the last few years LED’s have become very common as a source of light for us image-making types. As someone who in the early 2000′s started a company to produce LED lighting based fixtures for film and television, I guess I’ve known about the pros and cons for a while.
With such a highly monochromatic light source, even using red green and blue LED lights combined to make white, you still end up with a very “spiky” source of light. There are lots of colours that aren’t “lit” by the narrow bands of colour these LEDs emit. This means accurate colour reproduction is very difficult to obtain…if the colour isn’t emitted, then it won’t be reflected back to the camera.
White LED’s also suffer similar problems…they are usually blue LED’s that are doped to emit other colours, but usually very feebly.
When we look at the specs of these lights, we look at CRI or Colour Rendering Index, which describes how evenly across a spectrum of colours the light emitted will be. A high CRI is better than a low CRI. Tungsten is typically up around 99. Most KinoFlo’s are 90-95. A normal fluro tube might be as low as 80. Sodium vapour street lighting might be as low as 20-30.
Art Adams has done a very interesting comparisons of the commonly available LED based lighting. What it does show, is that LEDs still have a long way to go with regards to accurate colour reproduction.
So should they be avoided ? Of course not. but it helps to know that some lighting is more appropriate than others. If I want accurate and flattering skin tones, I probably wouldn’t want to be using LED’s. But they are great when you need low power and low profile lighting !
Have a look at the test here and click on how does it look bottom left…be surprised…
To see who the test was done go here
And yes, I still have the prototypes of the LED lighting units I had made at the time, including a ring light. I spent thousands of dollars, but was never really able to solve the same issues, much less get it to market.