Going LED means compromising on colour quality, right?
That was certainly the way things were when LEDs were the new kid on the block. Places like shops and galleries that needed faithful colour rendering were reluctant to use LEDs because of perceived poor colour quality.
Halogen was the gold standard for colour , and even if good-quality LEDs could hit a respectable colour rendering index (CRI) of 80 or so – fine for most everyday applications – halogen still had a clear edge.
Now, that’s all changed. One by one, the big lighting companies have been fine-tuning the recipe of LEDs and phosphors they use, and the cutting-edge LED products of 2015 can not only match halogen for CRI, but can make colours more vivid and whites whiter.
Xicato’s Vibrancy range and Philips’ CrispWhite range have now been joined by GE’s Reveal, promising ‘whiter whites’.
GE says its new technology, available first in retrofit PAR30 LED lamps, ‘brings out the most vivid colours and activates optical brighteners used in white clothing’, making whites ‘appear sharper, brighter and overall whiter versus a dingy, yellow appearance’.
So how’s it done?
For a long time, incandescent sources were the best available for colour, and were seen as the reference point for everything else. As a result, white light sources have stuck closely to the range of colours given off by incandescent, a range known as the black body locus.
But it’s not as if incandescent was perfect – an incandescent lamp with a warm colour temperature gives a nice cosy feel and makes reds and oranges look strong, but it will also make whites look yellowish. A cooler coloured lamp gives you nice ‘clean’ whites, but dulls the reds.
With LEDs, you can tweak the combination of chips and phosphors, and have it both ways – clean whites, and bright colours. You can even tune the light to stimulate the optical brighteners used on new clothes and in detergents to make whites seem whiter.
This is what the new products from the likes of GE, Philips and Xicato set out to do. It won’t necessarily be right for every application (research by Xicato found that natural objects like fruit or flowers could end up looking too vivid in some people’s eyes), but it gives retailers the flexibility to tune light like never before.