Blog: “Cheap as Chips” – the problem with cheap LED lighting
How to avoid the pitfalls associated with cheap LED lighting
Colour rendering and LED lighting
Improved colour rendering from LED
Colour rendering measures the accuracy with which colours are shown across the spectrum. LEDs have traditionally had a tough time rendering reds like the tomatoes in the banner for this page. A blue LED treated with phosphor sits at the heart of white LED light sources. One consequence of this is that LEDs have rendered blue better and struggled more with reds. That’s in contrast with incandescent sources like halogen that render colour across the spectrum effortlessly.
This uneven rendering of colour might not be immediately noticeable to the naked eye (though it can be very evident with poor quality LEDs) However people do notice that somthing is "not quite right" with the lighting. This is often attributed to the lighting being "cold" or dingy. Most likely, it's simply doing a bad job of rendering colour accurately; sucking the life and richness out of the space.
The good news though is that LED has made massive strides in accurately rendering colour and the very best produce truly beautiful light.
Why is good colour rendering important?
Think about the applications where you want the best rendition of a colour. Makeup lighting really needs accurate colour rendering and there is a lot of red in the colour of human skin even before you’ve considered the cosmetics. So as well as good shadow-free lighting, you should have accurate colour rendering on your wishlist.
Food preparation is another area where good colour rendering is important. We want our tomatoes to look like tomatoes not olives so if you’re considering kitchen lighting take particular heed of the Colour Rendering Index (CRI).
A higher CRI figure is one indication of superior colour rendering. A fitting with a CRI of 95 is going to have a better average rendition of the sample colours that go into the CRI standard than one with a CRI of 80. The photo below illustrates the effect poor quality LED light can have on colour, particularly saturated reds.
We select the best colour-rendering options available to us. We're slightly spoiled in that we can now access a variety of different light engines to fine-tune the light to suit the space it's lighting. It's something we can demonstrate to you if you visit our showroom and design studio.
CRI is an accepted and useful standard but it’s not without its critics.
Not least because the standard eight colours sampled in the CRI average don’t include a saturated red which can be measured as a separate standard. It’s possible we’ll see an alternative measurement supplement and potentially replace CRI in the future. There is momentum behind a testing system TM-30-15 which samples a wider range of colours said to be more representative of the colours we see in everyday life. This article was in part prompted by an article on TM-30-15 in Lux Review which is now sadly offline.
Standards are useful but we find it useful to supplement the bare figures with physical testing against specific finishes or materials. We’ve tested against brick, marble, different granites, artwork and even strawberry tarts and Fat Rascals. After all, if you’re lighting the cakes in one Yorkshire’s iconic tea rooms, you don’t want your raspberries to look like kumquats.
Credits
Tomatoes photograph is licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license. The photograph has been modified in the split screen picture to simulate the different colour rendering charateristics of different light sources.
See license details here.
Update
This page was originally published in 2016. It was significantly updated on 1/4/2024 to reflect the huge advances that have been made in the quality of the light produced by the best LED fittings. The Lux Review website is no longer online so the reference is retained but the link has been removed.
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