Frankfurt Licht + Bild comes around every couple of years and we all nip round to the chemist for a fresh tube of Foot Embrocation to keep us going. But the journey around the halls is more than a snapshot of what's going on in the lighting world today. We have to see the endeavour more like an archaelogical dig because what we see today has its roots in what happened two years ago, and two years before that. Or in the case of OLEDs, what's not been happening for the past decade and more.
Is this the end of the fluorescent lamp
The light's got brighter, it's gone 4000K all over, and it’s safe to say that the LED has finally taken over. There may have been some T5 luminaires around the halls, but if there were they were cowering in a corner somewhere, whistling to keep their spirits up.
But nostalgia for the fluorescent tube is widespread in the form factors of the luminaires, or maybe it’s just that manufacturers of industrial fixtures can’t be bothered to re-design their fluorescent fixtures and are just shoe-horning in LED boards.
Technical just got decorative.
Back in the day, when we were all young, the big beasts of the architectural lighting community demonstrated their chops by designing super-efficient reflector and louvre systems, and some of that kit was exceptionally good. Where have all the cat5 fixtures gone? It’s a rhetorical question because I don’t care and I’m glad to see the back of them.
We don’t need low-brightness luminaires anymore, apart from in the odd specialism, and our computer screens don’t need to be treated with such reverence, so where does that leave office lighting? This is not a rhetorical question, because technical lighting just got decorative. Welcome to the pear-shaped polar curve everyone!
It may be long and thin, it may be square or it may be round - but it’s still an opal diffuser, guys.
The end of the retro-fit lamp
Market analysts are forecasting the end of the retro-fit LED lamp, but it’s clear that no one's told the exhibitors at Frankfurt L+B. The E27 lamp in all it's finery and buffoonery, and all those myriad decorative fixtures are still going from strength to strength. I wonder, are any of the retro-fit lamps so good that we’ll be writing them into our wills, or will we see the usual profit-driven situation of lamps getting cheaper and failing earlier?
The Tunable Argument
There’s a bit of a brouhaha growing around tunable white sources. Versions are available using 2, 3, 4, 5 channels, and varying in their tunability ranges from 2500/6500K to 2000/3000K. But when one of the world’s major LED manufacturers puts up its collective hands and says ‘hang on a minute, we’re not sure about this’ then its worth taking time out to listen.
The issue is around the ability of the LED module to maintain its colour rendering qualities throughout the range from cool to warm. It’s an easy thing to use a high CRI cool white LED at one end and a high CRI warm white LED at the other end, but that’s no guarantee that the CRI will be maintained along the Planckian curve in between the two extreme values. And evidence to the contrary is widespread.
Know what you want to use colour tuning for. If it’s a limited range, such as mimicking the dimming curve of a tungsten source, for example, then maybe a 2-channel option is fine; there’s not much room for off-Planck activity across 1000K. But with far more talk going on about lighting to support circadian rhythm, it may be necessary to insist on CRI information along the entire journey round the Curve. The product is out there, but there's a lot of cheap stuff making a lot of noise.
Chasing the light dragon
As well as chasing white light up and down the Planckian Curve, LED companies are also turning their attentions to colour metrics and the way in which colour rendering is reported.
Although TM30-15 (IES Method for Evaluating Light Source Colour Rendition, for those of you not paying attention) hasn’t yet been accepted by CIE, there are companies taking advantage of tan improved method of reporting colour accuracy. Xicato, in particular, are happy to demonstrate how accurately their Artist and Vibrant series echo the curve set by the reference illuminant. It’s an impressive gallery of performance.
Walking among the exterior lighting displays I felt like I was intruding on the Gathering of the Ents before they went off to destroy Saruman’s lair at Isengard. Some of those street lights looked very angry indeed.
I think that there’s something going on here that’s not being picked up by the goniophotometers and it may be something that has repercussions beyond street lighting design. Manufacturers are confident that their luminaires are working within accepted parameters and I acknowledge that. But that doesn’t mean that there is no glare problem. There is a glare problem.
It could be that the discomfort is associated only with the higher range of colour temperatures and, for sure, blue-rich sources being used in residential streets has been at the heart of the argument. But it could be that we’re experiencing a different kind of glare, directly attributable to the point-source nature of the individual LED module. And if that’s the case, then we need to be looking more closely at our testing procedures.
The case for SON nostalgia
I was surprised to see a return to the warm yellow tones of the of SON lamps; it made me think of cloth caps, bull terriers, and nicotine-stained ceilings. And that was just my gran.
But there are practical reason why amber street lighting could make a comeback. Using a dominant yellow light is perceived as being more comfortable to the viewer, produces less sky-glow and, if we insist on needing light in the first place, has the least impact on nocturnal species. Of course, it’s not as efficient as a blue-rich source, but this is an argument that puts creature comforts (literally) ahead of brutish cost efficiency.
I tested out the phrase ‘melanopic lighting’ on a few of my friends at L+B and am glad to report that the general reaction was confusion followed by fear, in case they’d missed something that they should know all about.
I attended the seminar session held by Lighting For People, joining the platform speakers for the final Q&A session. All of the science is pointing towards a better understanding of how we should manipulate our artificial lighting towards building a visual environment that works in our favour, supporting us during throughout the day.
Melanopic lighting describes the process by which we’re able to deliver lighting that has a spectrum that has been designed to provide the correct frequency of blue, around 479nm, to assist in maintaining attention levels while we work. This much I knew already.
What I didn’t know was that shift workers can be helped in a way that supports their personal circadian rhythm. Lighting at night shouldn’t contain enough light to trigger melatonin suppression, but it turns out that attention levels can be maintained by boosting illuminance levels using a far warmer light. But we must then review the CRI properties of near-zero-blue light at levels in excess of 500lux, and that’s a new concept.
But I wonder to what extent melanopic lighting will serve any practical purpose for the majority of us who spend our days in what passes for a natural environment.
The shift towards Ra90+
I’ve been warning architects not to get romanced into claims by lighting companies that they need Ra90+ LEDs for their projects. After all, most of us have been perfectly happy to co-exist with Ra80+ lighting for a good number of years now, so why add cost to the project if it’s not necessary.
If there’s a practical thing going on here, like the shift from halophosphate to tri-phosphor fluorescent lamps, and LED manufacturers are considering the optimisation of their LED production so that everything is Ra90+, then that’s fine, but I can’t see the point if paying over the odds for colour accuracy that’s not needed if Ra80+ sources are available.
The Internet of Things
I’m amazed to announce that I’ve been won over to the argument in favour of the Internet of Things. I still think it’s a silly name and reading about my refrigerator having conversations with my toaster and ordering a new loaf of bread from the supermarket makes my toes curl. But I acknowledge that there is a dense stratum of sensibleness to be mined from the idea that we can communicate with your environment via electronic sensors in everyday objects.
Just leave my toaster alone.
I went to Frankfurt on the back of a number of conversations about the growing use of lenses in LED luminaires to shape the light pattern beyond the usual narrow – medium – wide beam distribution. And I have to admit to being disappointed in what I saw.
There are two sectors that are making a lot of use of lenses, those being street lighting and the automotive industry, but architectural lighting companies have been slow on the uptake, even though the lens manufacturers are there waiting to take the call.
There is a handful of companies making use of the optical engineering that’s available but I sense that it’ll be some while before many LED luminaire manufacturers reach the point of realizing that lighting designers sometimes want light that goes sideways, not just downwards.
One of the I-Spy games that I play is Hunting The Buzz Word. You know that something is trending when the same words appear on exhibition stands, in catalogues and on websites. But it’s just as interesting when things that should be buzz words make hardly any appearance at all.
‘Sustainability’ was a buzz word a couple of years ago, and plenty of lighting stands were given a liberal coat of green-wash to keep tree-huggers like me happy. But this year, there’s hardly a mention. Now, if I was in a positive mood I’d suggest that sustainable practices were now so embedded in company culture that it hardly registers a mention . . . but, nah. I don’t think so. I think we’re back to business as usual.
Which is a pity because the next buzz phrase is hurtling down the tracks towards the lighting industry and this one might be the thing for everyone to take notice of, because it’s about saving money – or perhaps making more money.
The Circular Economy is currently conspicuous by its absence, though I did notice one cradle-to-cradle accreditation down in the halls; a shout-out to Sapa there. In two years’ time, we may see more manufacturers talking about how re-usable their fixtures are.
Two materials are overwhelmingly in evidence in current luminaire design: plastics and aluminium. The use of plastics is an enormous global problem that can only be resolved by shifting to sustainable practices that enable the material to be recycled or composted at the end of life. Aluminium is a fantastic metal and, at first sight, is the obvious choice as a sustainable material in product fabrication. The problem here is one of global success. Far more aluminium is in use today than we would ever have imagined was possible, and that means more virgin aluminium being produced from more bauxite mining - which isn’t very nice. The aluminium recycling process also uses energy that could be saved if we moved towards a process of re-use, rather then re-processing.
The Ghost at the Feast: the OLED
The best lighting product that there never was. Watching the couple of stands featuring OLEDs from a distance felt like the last hurrah from an old campaigner who showed a lot of promise but never actually came up to the mark to fight it out in the ring. Some of the moves still bring a round of applause but, overall, we know it’s all over. Time to throw in the towel and ring the bell.
And that was Frankfurt Licht +Bild until 2018. Let's see what happens next!