TECHNIQUES 7: The backlit panel

July/August 2010 | By Lauren Vanderkar

Mindseye director Doug James explains why the backlit panel has held its place in architectural lighting design for four decades

Many techniques discussed in this series are fairly recent incarnations brought about by changes in architectural design and technology. But every so often there’s a concept that stands the test of time, earning what Doug James would call a “decent pedigree”. Interestingly, the backlit panel is a prime example, having remained relatively unchanged since its conception in the late 60s. “There are quite a few significant examples in popular culture,” confirms James. “It goes back a long way.”

Origins
Despite several iconic examples, the backlit panel has its roots in basic and rather primitive office lighting. “The 1970s saw office environments pioneer the use of wholly illuminated ceilings. It was a pretty unsophisticated method of backlighting using a series of polycarbonate panels on a grid. It didn’t look great but it was an interesting development at the time,” says James.

Then, with the advent of office computers in the 1980s, the backlit panel fell foul of VDU guidelines and disappeared from offices altogether. “The first kind of computer had a black screen, so any white glowing service would reflect onto the screen and stop people from working,” explains James.

But once a white, self-illuminated screen was introduced in the 90s, these issues became much less prominent and a move towards homogenous lighting saw the backlit panel return with a vengeance. “It started appearing in all kinds of spaces,” says James, who regards the popularity surge as a new found appreciation of backlighting. “It wasn’t considered to be retro; just a greater understanding of the lighting technique where it was most relevant.”

Modern examples
It holds particular relevance where there is little or no access to daylight. Tequila bar in London’s Soho was an interesting scheme that doubled as a corporate space during the day and a bar in the evenings. “The whole place was sub-ground so had no natural daylight, but still needed to feel bright and airy for corporate meetings.”

For James, the best solution was a series of wall panels backlit with a clean white light during the day, with the ability to radically alter the mood at night by changing the colour and level of the light.

“The light source behind the panel is crucial. Get it wrong and you’ll completely destroy the effect”

T5 fluorescent and cold cathode lamps are commonly used to backlight the panels, although T8 has its uses here because the surface brightness is weaker, hiding the outline of the lamp more efficiently.

And of course there’s LED: “It’s costly but it can be done,” says James.

The technique’s sleek design and even glow flourished after the introduction of ceiling membranes like Barrisol, which did away with the unattractive grid effect of the 70s.

As the backlit panel became more of an aesthetic piece, contemporary gallery spaces used it to provide homogenous lighting across art installations and sculptures. A better known example is the Tate Modern, although the technique was actually used at White Cube Gallery’s Mason’s Yard site a couple of years earlier. Here, Mindseye drew on natural and artificial lighting behind a series of ceiling panels to provide even luminance throughout the space. “Even where daylight is available, you need to be able to control it. We used panels to manage the levels and temperature of light,” says James.

It’s this mix of high functionality with sleek aesthetic design that gives the technique its unique staying power in the world of architectural lighting. In modern corporate spaces, James notes the prominence of the backlit panel in modern corporate spaces, especially reception areas.

“Whole ceilings or a major wall panel can be backlit as a feature or a predominant light source, or both,” he says. Similarly, the Barbican Arts Centre set Mindseye the brief for a backlit wall that acted as the predominant light source “but it also became a key feature in the space,” adds James.

Three things to remember
As with any technique, there are pitfalls to avoid.

1. “The light source behind the panel is crucial. Get it wrong and you’ll completely destroy the effect,” warns James. The depth of the luminaire is important here – too deep and the light source will be visible behind the panel. “In some cases people like to see the muted glow of the tubes, but as an architectural panel within a space, you generally want an effect that’s even and lamp-free.”

2. The second point is accessibility. “There’s a lot to consider here,” James begins. “The lighting still needs to be cleaned and maintained even if the panel is horizontal and on the ceiling. The type of material used for the panels is important, as is the ceiling membrane. There are a number of foibles to be aware of, so lighting designers need to really get involved with the architect and the material suppliers to make sure every detail is right.”

3. James’ final tip underlines just how important forward planning is in the design and installation of the backlit panel. “One thing we’ve always done, especially when we had less experience of this technique, was to create a full scale mock up. Make sure you’ve got the lamp measurements right. If you haven’t worked out every detail, you’ll certainly be in for some nasty surprises.”