Shine On: part two

In the afternoon Graham Festenstein, lighting consultant, kicked off a discussion about using lighting as a tool for interpretation. New technology, he said,  especially LED, presents new opportunities, “new revolution” in lighting. It’s smaller, with better optics, and control. And also more affordable! He used cave paintings as an example. Lighting designers could take one of three approaches to lighting such a subject:  they might try and recreate the historical lighting which, for a cave painting, would have been primitive indeed,  a tallow bowl light, revealing small parts of the painting at time and with an orange light; it’s more likely, given the needs of the visitor, that they might go for more wide angle lighting, revealing the whole of the painting at once; or, they might light for close up inspection of the work, to show the mark making techniques. Traditionally, a lighting designer would have had to chose just one of these approaches. But with the flexibility and versatile control of modern lighting technology, we can do all three things – caveman lighting, wide angle panorama, and close up technical lighting.

Graham’s presentation was not the strongest. heexplained that he was sceptical about LED lights at first pilot as a sceptic. He recalls a visit to a pilot project at the National Portrait Gallery. His first impressions were disappointing, but then he realised that what heith missed about the tungsten lighting to the way it it the gilded frames, and the the LED lighting was better serving the pictures. Then he went on to talk about colour, how the warm lights of the Tower of London’s torture expedition undermined the theme, but the presentation overall was somewhat woolly.

Zerlina Hughes, of  studio ZNA, came next, with a very visual presentation which I found myself watching rather than taking notes.It explained her “toolkit” of interpretive lighting techniques, but I didn’t manage to list all the tools. A copy of the presentation is coming my way though, so I might return with more detail on that toolkit in a later post. One of her most recent jobs looks great however, and I’m keen to go. Say You Want a Revolution, at the V&A follows on from the Bowie show a year or so ago, but with (she promises) less clunky audio technology. I want to go.

Jonathan Howard, of  DHA design, explained that like Zerlina, “most of us started as Theatre designers.” I (foolishly, I think, in retrospect) passed up an invitation to do theatre design at Central St Martins, and I think I would have been fascinated by lighting design, if I had gone, so I might have ended up at the same event, if on the other side of the podium. Museums audiences today are expecting more drama in museums, having experienced theatrical presentations like Les Miserables, and theme parks etc. I was interested to learn that in theatre, cooler colours throw objects into the background, and warmer colours push them into the foreground. This is apparently because we find the blue end of the spectrum more difficult to to focus on. In a museum space, he says, you can light the walls blue so that the edges of the gallery fall away completely. But he did have a caveat about using new lighting technology. Before rushing in to replace your lighting with LEDs and and the modern bells and whistles, ask youself:

Why are we using new tech?
Who will benefit?
Who will maintain it?
Who will support it?

Kevan Shaw, offered the most interesting insight into the State of the Art. He pointed out that lighting on the ceiling has line of sight to most things, because light travels in straight lines (mostly), and we tend to point it at things. So, he said, your ligthting letwork could make a useful communications network too. He wasn’t the first presenter to include and image of a yellow centered squat cylinder in their slide deck. And they spoke as though we all knew what it was. I had to ask, after the presentation, and they explained that it was one of these. These LED modules slip into many exisiting lamps or lumieres. They are not just a light source, but also a platform for sensors and a communications device. Lighting, Kevan argues could be the beachhead of the Internet of Things in museums.

He briefly discussed two competing architectures for smart lighting, Bluetooth, which we all know, and Zigbee, which you may be aware of through the Philip’s Hue range (which I was considering for the the Chawton experiment). He also mentioned Casambi and eyenut, I’m not sure why he thinks these are not part of the two horse race. He argues that we need interoperability. So I guess he’s saying that eventually the competing systems will eventually see a business case in adopting either Bluetooth or Zigbee as an industry standard.

With our lightbulbs communicating with each other, we can get rid of some of our wires, he argues, but it needs to be robust, reliable. And the secret to reliability is a mesh networking, robust networks for local areas. Lighting is a great place for that network to be. That capability already exits in Zigbee (so I think zigbee is what I should be using for Chawton), but its coming soon in Bluetooth. And I think Kevan believes that when it does, Bluetooth will become the VHS of the lighting system wars, and relegate Zigbee to the role of Betamax.

But the really exciting thing is Visible Light Communication, by which the building can communicate with any user with a mobile device that has a front facing camera (and the relevant software installed. He showed us a short video of the technology in Carrefour (mmm the own-brand soft goat cheese is delicious).

The opportunities for museums are obvious but, he warns, to be effectively used, museums will need resource to manage and get insight from all the data these lighting units could produce in resource. Though he says optimisticly to his fellow lighting consultants, “that need could be an opportunity for us!”

Finally we heard from Pavlina Akritas, of Arup, who took the workshop in the direction of civil engineering. Using LA’s Broad Museum as an example, she explained how in this new build, Arup engineered clever (North facing) light-wells which illuminated the museum with daylight, while ensuring that no direct Los Angeles sun fell directly onto any surface within the galleries. The light-wells included blackout blinds to limit overall light hours and photocells to measure the amountof light coming in and if neccessary, automatically supplement the light with LEDs. She also talked briefly about a project to simulate skylight for the Gagosian gallery, Grosvenor Hill.

All in all, it was a fascinating day.

This post is one of two, the first is here.

Shine On: New Perspectives on Museum Lighting

Yesterday I attended a workshop organised by the museums association and hosted by Stephen Cannon-Brookes, of UCL Bartlett School of Architecture and lighting consultant. I was there for work, but found it useful for my studies too.

To be honest, it wasn’t all about “New Perspectives” as such, it covered a lot of the the established ground too. But for a non expert like me, that was incredibly useful. It was also an opportunity to showcase the Society for Light and Lighting (SLL)’s Lighting Guide 8: Lighting for Museums and Art Galleries, though at £80 (£72 for the PDF) I won’t be rushing out to buy it. More of an institutional purchase I think. The first speaker, Paul Ruffles, talked us through that guide.

Beautiful objects in beautiful buildings deserve beautiful lighting.

It covers lighting principles, and stuff like visual adaptation, contrast ratio, colour appearance, colour rendering, glare, lighting the interior or display area, day light, electric lighting, access and security and emergency lighting (he explained that one unnamed city museum experienced a spike in consumption they couldn’t explain until they worked out  a security guard afraid of the dark was turning all the lights on at night). The book its just for white box galleries, it also talks about historic interiors; temporary galleries; events and corporate entertaining; the shop and of course the cafe.

He explained that since the pulication of the previous version, LED lighting has become a useful tool in historic interiors, citing an example of Chatsworth’s great stair. Historic interiors need some obvious light sources, standing lamps and the like, but hidden ones -tiny LED spots in to the historic lighting can bring out fascinating details.  However, he warned that when lighting historic places, the LED unit might only cost £28, but the wiring costs hundreds.

His talk was littered with useful tips and anecdotes. Things like keeping track of the spare parts your supplier gives you – I can well believe that when they are needed, no one can remember who put them where. He points out that when you are planning what goes on the floor in your exhibition, you want to think not just about access for wheelchairs, but also access fro whatever cherry-picker or quickup tower you need to replace the lightbulb. Lightbulb replacement is getting less of a need as LED takes over from tungsten, but LED lights can still occasionally fail. And, if you need a five tonne cherry picker to get to the lights, make sure the floor can take five tonnes (and remember it’s turning circle).
Manchester City museum, wall of paintings all lit individually between 50 lux to 150 lux.
material degradation,

Next up was David Saunders of the  International Institute for Conservation talking about The Balancing Act: Light, Conservation, and Access. He started off asking how much light to visitors need to see objects, there is evidently a rule of thumb that the minimum is 50 Lux. But he showed us a  a Durer woodcut and a Turner Watercolour. The Durer needs just a few lux, it’s black and white, and high contrast. Reduced contrast such as in the Turner, increases light needs by factors of 10.

Gary Thomspon’s The Museum Environment was a very influential book, but most of the research that informed it was experiments done in university’s , with populations of students with (being generally younger) better eyesight than the average museum visitor. So a sixty five year ol needs 300 lux for the same performance as a 25 year old at 10 lux. Similarly Colour matching ability peaks in 20s. The ability degrades as you get older. The colour differentiation you can discern as a 20 year old at 10 lux, requires 1000 lux in 75 year old. There are other factors too, which may be less relevant in museum environments, like visual task difficulty (it takes less time to see things in brighter environments).So he points out that a object that we might think needs just 50 lux to see properly might actually need three times as much for older views. Another three times if it’s a low contrast item, which means as much as 500 lux. Ifs it’s a darker object, or a difficult visual task it might need even more.

He went to to explore the history of the research that has led to those squares of blue wool you might have seen dotted around museums and National Trust places. The “blue wool” number has now become an international standard, where 1 fades quickest, and 8 shows the least discernible fading in the same period of time. It turns out that the same amount of damage occurs if you expose something to twice the light for half the time, so, we can think in terms of exposure doses, or lux/hours. The key learning from all this research is to limit the overall exposure to light. He swings by considering the differing levels of damaged caused by different wavelengths of light, mentioning the red/green skylights installed in the roof of the V&A’s Raphael gallery, before concluding that the key learning is to exclude UV radiation.

Then he addresses an interesting question. How long should an object remain unchanged In fact, there’s remarkably little research in this area, and it doesn’t seem that wide-ranging. I drifted off into thinking about an exhibition that explains these issues, and then gives some options asks the visitor how long a selection of items should last “unchanged” (of course what that really means is little or no visible change). What work has been done, David says, broadly concludes a desired lifetime before change of something like 100-150 years.

All this, he concluded, means that when thinking about this, there are very few variables that we have control over. The amount of “acceptable” damage from light is set by the objects desired lifetime, the light dose is set by the object’s sensitivity, and the level of light is set by human need – therefore length (time) of exposure is the only variable we have that’s really under out control as heritage professionals

Then Jo Padfield, conservation scientist at National Gallery, gave us a great talk on all the research work going on there. He started off questioning our arbitrary decisions on lifetime by showing us Paolo Veronese’s The Dream of St Helena, wherein she looks out on a sky that, in his words resembles:

a dull grey afternoon in Glasgow

But closer examination shows it was painted with Smalt, which was Mediterranean blue, and padfield showed us what that might look like. similary, the grey/blue bedsheet of the Rokeby Venus was once royal purple.

he talked a little bit about the change from tungsten bulbs (adjustable in increments of 60, then 30 lux to LEDs to have more control, dimming in 10 lux increments, as well as energy/CO2 reduction. There was an issue with colour quality and consistency of the new LED lamps, so they created an internal website to monitor and research the change to LED lighting. This website is now open to everyone, and some of the audience explained how useful it is.

He also mentioned the Making Colour exhibition in 2014. At the end, he said “we experimented on visitors. Human perception experiments are normally done in the lab with a sample of about 6 people. Our sample was 20,000.” He showed us how unter different bulbs, people saw the same painting differently, in one still life the same fruit could be orange or  yellow,

Jo Beggs, Head of Development for Manchester Museums Partnership, finished the morning with an explaination of where they got funding for improved lighting for the recent, £15 million redevelopment of of the Whitworth museum, especially when the lighting costs went 25% over budget.

There was lots more to talk about after lunch, but that will have to be another post tomorrow.