If Form follows Function, what shape is an LED? Chris Fordham reports on the success story that is the linear phenomenon.
Back in the day if you wanted to wash an external linear feature, or cabinet, cove or cornice, your options were quite limited. If it was important to get the perfect colour rendering , xenon lighting was your baby, it gave a crisp warm white and lasted up to 20,000 hrs, but was warm in all senses, food, fresh flowers fruit would all be toast, quite literally.
Then there was the fluorescent option. Great for coffer ceiling and wall details with T5 and T8 versions, but a real bummer if you had a detail length that didn’t match the lamps dimensions. Colour rendering wasn’t the best but possibly worse, was when contractors just butted up the lamps together top to toe, leaving shadow gaps all over the place, in many cases the best you could say was that it looked amateur.
(Editor’s note: you do realise that there’s a whole generation of lighting designers who don’t know what you’re talking about!)
Fast forward to nowadays and there is a plethora of choices, and the design community has really taken the flexibility and size of the products to their collective hearts. I remember working with Zaha Hadid on a project where this form of lighting was all that was allowed, the architecture should do the talking, and the light would follow its form.
As with any lighting it is important to consider the fittings you want to use well before construction has begun; dimensions of products can differ greatly, as well as the beam angles and lumen outputs. These will affect how the depth of space will be perceived.
For Bruce Weil of the Lighting Design Studio, linear led strip offers several advantages over previous sources, but working with it brings its own set of challenges.
“One thing that people forget is that you still have the peak intensity that doesn’t really exist on cold cathode; the chip itself is the brightest part, and it has caused us issues in some projects. One company who has solved that particular problem with its remote phosphor technology is Vexica, (Flexiline: shown right:) the flexible version means you can follow any bends in the coffer or wall detail.”
Bruce also highlights the difficulty and importance of getting correct dimensions,
“When it comes to coffers, alcoves, drop ceiling, or any type of cornice detail, always having the correct dimensions is paramount, and install requires a lot of cross checking with builders and electricians.
Problems can occur when products are made to order with specific sizes, we have had projects where dimensions on site do not match the original drawing, then you have a product that can’t be used on this project or any other. The other side of the coin is when it is supplied in kit form, then you are at the mercy of the contractor to install it perfectly, which doesn’t always happen.”
(Image right: Sotheby’s London: by Lighting Design Studio)
Project architect Andrew Clapham also gave his pearls of wisdom from the numerous projects he has been involved in,
“Coffer, coves, recessed and ‘invisible’ sources certainly are an especially useful way to highlight particular elements, and we often use them to create a hierarchy of interest. It does start with the client, who must be interested in highlighting an element in the first place, and I am a firm believer that it is really important to get the lighting designer in from the start, for the best results.”
In conversation with Tom Miller, currently the director of ILC lighting, Tom finds that the use of linear lighting for him is ubiquitous,
Tom: “Almost every project I work on has some form of linear lighting in it, but to varying degrees. It could be anything as simple as soft indirect lighting under a floating vanity unit in a loo, through to coffered ceilings, cove details, but always on a project by project basis, you have to be careful not to throw these things in for the sake of throwing them in, and make it bespoke to the kind of property or client you are dealing with.”
Chris: “I have heard of projects where maybe they have not considered dimming, which for that type of lighting can be a problem; I think people can underestimate how bright these luminaires are nowadays, and they can literally drown out and destroy any sense of nuance you are trying to create in the space.”
Tom: “Dimming is really important, and I would use it with linear led without exception, because as you say when you are dimming with an indirect luminaires it creates quite a volume of light in the room, whether it’s a coffered ceiling, or a cove detail, it’s still going to bounce it all back into the space. You ordinarily use a good few metre of linear led and that means a lot of lumens. Also, you must be careful to consider the technical details of your driver, to make sure it all works perfectly you need to know its capacity and dimming compatibility, making sure you haven’t over specified how much tape is on one driver, or power supply. This is important to prevent linger or inconsistent dimming. You need to be in control of all those factors to implement the design well.”
Chris: “That level of detail is so important; do you find yourself using a similar palette of products?”
Tom: “When it comes to tape, I use products that are linear, or for the curved details the silicone Lumiflex type product; it’s a solid sort of sealed led with a diffused side and three opaque, which can go round bends making circular coffers and bendy details easy. The company I tend to use is Atmospheric zone, who provide fantastic support. There is so much on the market but sometimes with the cheaper stuff the colour rendering isn’t that great, and it just doesn’t have the same longevity. It is a lot more complicated specifying linear product over say a downlight, so product support of the company is so important”
Chris: “What are the biggest drawbacks?”
Tom: “With linear lights it’s a strong effect which is part of the fabric of the room, you don’t want to do it for the sake of doing it, but because the architecture and design is driving it. A classic mistake is when you up light a surface that is irregular, it can show up all of the imperfections, so you have to be aware of what it reveals in a space as well as what in enhances, because that can be a big problem. There is nothing worse than highlighting all the imperfections, do not crowbar these lights in, the role of the lighting designer is to decide what looks the best, even if that means just using a central pendant and that’s it.”
I think the take home from our panel of contributors can be summed up as with many experiences around LED – quality of product and good lighting design matters. Be aware of the pitfalls which may at first not be immediately apparent, and do not try and shoehorn in linear led solutions where they are not suited to the architecture, Linear LED is here to stay and we have a vested interest in being the go-to people in specifying it when and where appropriate.