LED Lighting in Art Galleries and Museums

At last a lighting technology has arrived which can genuinely do it all. Yes it can save all those maintenance hours changing light bulbs, it uses less than half the energy consumed by “energy saving” compact fluorescent technology and because each lighting element is a semi conductor, it can be controlled with ease. It also projects no Infra red and no Ultra Violet, the two specific elements which damage art and artefacts. What is more is that the bit that emits lights is also very, very small. Having said all that this technology is very, very new.

An art gallery really needs lights that do not need changing - often the light sources are very high and require at least two people, and often scaffolding to change one light. They are obliged by law to show their energy consumption and are therefore keen to reduce that energy bill. They have a range of items in their collection - some of which would show to best effect in a warm light, others in a cooler light, all needing to be as near to daylight in colour accuracy to project the artefacts to best effect. Most importantly all light sources damage the artwork and so much effort is made to reduce the amount of light on the actual collections - please see the British Galleries in the V&A or the Smithsonian Museum of America to witness where light levels are so poor that the much prized artefacts can be barely made out.

Recognising these enormous benefits the museum and gallery markets are piling into this new solid state - LED lighting. The energy reductions are dramatic and the lights do not fail. Furthermore there is no damage being done to the artwork. And yet to my judgement the galleries where these are installed completely fail to light the work sympathetically. The colour temperature is uniformly cold, the narrow beam angles make for a “hot” spot right in the middle of the cherished art work with much lowers light levels over the remainder of the work, and the light fittings themselves are astonishingly ugly with a series of white lights glaring.

How has this come to pass? Given that the technology can deliver all the stated benefits and that the payback certainly justifies the investment, why is it that so many sites have bought into compromised solutions?  The answer seems to be that the savings benefit is what has driven the change and not the aesthetic demands nor a complete understanding of what the technology can offer. It is considerably easier for a Building Services team to turn to their old supplier of art lighting and ask them for LED art lighting than it is for them to really learn up on the technology and understand how to assess what the technology can deliver and who can deliver it. The real experts on this technology are not the great brand names of historic lighting but electronics specialists dotted around the country - yes the UK has some of the very best thinking and expertise in the world.

The answer must be for the curatorial teams and building services teams to engage with the thinking of the technology experts. Both parties can then truly understand what each needs and what each can offer. Once each understands the other, clear specifications can be drawn up which determine the criteria required. Only then should we be commissioning LED lighting which genuinely suits the extraordinary collections we enjoy and the artworks they hold.

Ian Peter MacDonald, Norwich, June 2012

Select LED lighting

When Edison approached his customers with the first lightbulb, did they go to their existing candle and gas fitting suppliers to ask them how to judge that bulb ?

LED lighting is the current buzzword for an easy route to reducing energy. Simply change your light bulb and you will save energy. The mantra is commonly accepted and household, builders and commercial enterprises are all rushing to make that change.

And yet this is completely unregulated technology. How do the consumers know what to buy ? The product claims “equivalent to 50W halogen downlight, lasts for 50,000 hours, guaranteed for 5 years”.  Let us examine these claims:

1)      Equivalent to 50W halogen. In what respects ? It may mean that the fitting suits your existing 50W fitting. Does it mean that the light output is the same ? Light output is  defined in lumens and a 50W halogen light generates over 800 Lumens. There is not one single LED lamp which generates 800 Lumens. Does it mean that it is a familiar warm light which dims to a satisfying orange glow ? A 50W halogen has a colour temperature of around 2600Kelvin which warms up to around 2200K at a low dim level. No LED lamp on the market today can emulate this. There are LED lights which can achieve a genuine equivalence to a 50W halogen but they are specialist products.

2)      Lasts for 50,000 hours. An LED can last for 50,000 hours - ie around 8 years with the lights on all of the time, but how much light is generated at 50,000 hours and what colour is it ? Unless you know exactly the testing conditions and the anticipated Lumen output reduction rate, unless you understand the heat dissipation mechanism and the anticipated catastrophic  failure rate your LED lights will be a range of different colours and really rather dull in 50,000 hours.

3)      Guaranteed for 5 years.(Some manufacturers claim 10 years). Guaranteed to do what in ten years ? Yes they will probably be on, but how do you assess what is too dark or what colour shift is covered ? What will the manufacturer do when you call up and claim new fittings ? Even if they do replace them, how do you guarantee they are the same colour temperature, the same LED bin, the same light output and even the same bezel colour as the original. After all, replacing one will look rather odd against all the others unless you really have that answer.

The truth is that as in any ground changing technology there is a desperate fight as the established lighting suppliers, who have made their billions exploiting a technology created over a century ago, jostle with the young hi tech engineering  turks who really understand the technology, who push the envelope and who are genuinely offering a brighter, better world of light. We, the modest consumers are merely pawns in this battle.

This leaves the professionals in a bit of a jam. A builder or electrician is obliged to provide Part L2 compliant LED lighting. Supply inadequate LED lights and you get an unhappy customer, or the compliance officer will reject them and new lights will have to be sourced. Architects are constantly swamped with handsome brochures showing handsome LED light fittings. They cost a fortune, yet how does that architect judge how much light, what colour they will be and what dimming system will work, as well as the issues of longevity and colour maintenance.

The light output from every single LED manufacturer is different. How do you know if that light will provide the light you need ?

So, if good LED lights do exist, where do you get them ? The answer is to employ a specialist lighting designer who will layout the lighting and define the exact LED light for that job. The responsibility is then on them to support the claims with proven tested criteria and to manage the guarantee. They can model the light levels and show you exactly what light you will get before you make any purchase. Yes there will be a slight cost - a lighting designer will cost around £400 a day, but that is small beer relative to choosing the wrong LED lights.

Ian Peter MacDonald - MacDonald Tait Light - ianpeter@macdonaldtait.com - 24^th October 2011