tonymaslen Posted May 7, 2003 Share Posted May 7, 2003 As LED technology is coming to the for front, does not come close to producing the heat that a normal tungsten envelop produces, why are they not used in the theatre to light the stage? Link to comment Share on other sites More sharing options...
peter Posted May 7, 2003 Share Posted May 7, 2003 LED lighting is currently undergoing a lot of development, with the first theatrical products coming out, such as the PixelPar - a parcan with LEDs. The main problem at the moment is the brightness - a Par64 fitted with LEDs produces around 9000 lumens at source, but this drops off to something like 50 lumens when you get to be 5m away. I was quoted a figure of 18 months by a James Thomas Engineering employee, effectively meaning that brightness doubles every year and a half. So in short, LEDs are coming - just not yet. I expect we'll see a few new products at PLASA, from Pulsar (Chroma range) and James Thomas (Pixel range). Someone (can't remember who) also had an LED moving head, but it was very gimmicky and not bright at all. TV on the other hand... LEDs are already there. Just watch the Lotto draws every week for a great example. Another problem with LEDs is focussing. They're fine for wash lights, but due to the way the light is produced,its very hard to focus it down into a sharp edge. This will need to be overcome before LEDs are commonplace in the theatre. Link to comment Share on other sites More sharing options...
tonymaslen Posted May 7, 2003 Author Share Posted May 7, 2003 cheers for that, so how long do you think it would be before we start seeing LEDs taking over on the wash front with in the theater are we talking a few years decaded or centuries? Link to comment Share on other sites More sharing options...
peter Posted May 7, 2003 Share Posted May 7, 2003 Give it a decade, and there will be a west end show with LED front light.... thats my mystical projection anyway Link to comment Share on other sites More sharing options...
tonymaslen Posted May 7, 2003 Author Share Posted May 7, 2003 can I quote you in my dissertation? Link to comment Share on other sites More sharing options...
gareth Posted May 7, 2003 Share Posted May 7, 2003 Topic moved from Safety Forum to Lighting Forum, 7/5/03 Link to comment Share on other sites More sharing options...
Ian Ferguson Posted May 7, 2003 Share Posted May 7, 2003 LED's are being used a lot in scenery though with some very clever effects being produced. Try the car in Chitty Chitty Bang Bang, there are LED light sources all over that. Link to comment Share on other sites More sharing options...
Guest lightnix Posted May 7, 2003 Share Posted May 7, 2003 Give it a decade, and there will be a west end show with LED front light.... thats my mystical projection anyway Almost certainly, but you're more likely to see them in the foyer first - LEDs are appearing most frequently in architectural projects at the moment. It's also likely to be a long time until you see LED based profile spots. The basic advantages of LEDs over tungsten (apart from low heat) are:Energy efficiency - LEDs are 90% energy efficient, compared to around 10% for tungsten.Mechanical reliability - no filament to break, the light producing chip is enclosed in an optical grade resin. They don't tend to break if you drop or bash them.Long Life - If not overdriven, LEDs will shine continuously for 100,000 hours, that's 11½ years non stop without burning out, although there may be a drop in light output of around 30% by the end of that period. Many companies do overdrive in order to raise the brightness, but you are still looking at a "lamp" life of 10,000 - 50,000 hours.Size - They are so tiny, you can build them in to almost anything (i.e. Chitty). The current disadvantages are:Low Output - Despite continuing huge advances, LEDs are just not as bright as tungsten - yet. They will be eventually, though.High Initial Cost - LEDs are expensive at the moment. Individual blue or white ones cost almost £3 each from Maplin, although Farnell do some a bit cheaper. Lighting Direct sell LED MR16 ("birdie") replacement modules - at around £55 each ! Many of the Pulsar Chromarange units weigh in at about £250 and the last price I heard for their LED battens was £4000. OK, there are huge long-term savings to be made in electricity and maintenance bills, but getting people to shell out for them in the first place is going to be tricky, especially in theatre where (as we all know) there is little or no money. I've been talking to a few exhibition designers about LED lighting recently and although they are fascinated at the possibilities, they are all a bit put off by the cost. Given the amount of 40 year old equipment out there, it's going to be decades before LED lighting becomes the norm on stage. Manufacturing costs are falling, though, at around 10-12% per year at the moment.Colour Consistency - Not such a problem for coloured LEDs, but still a bit of an issue for white ones (which are actually blue LEDs with a phosphorous coating on the chip). Some come out a bit greener, others a tad blue or yellow. For this reason LED manufacturers "bin" their products according to the purity of the whiteness they emit. There are also a few stories of coloured LEDs losing their purity over time, but I'm not sure over how long. Even so, LEDs are coming and the revolution is already underway. It's possibly best to regard LED technology as being at a kind of "Vari-lite VL1" stage of development right now - a bit basic, but with huge potential. The LED moving light at PLASA last year was called the Droplet and was developed by a young Dutch company called Xilver. I believe that Lightfactor are the UK distributors and they cost around £849 each. I did a couple of gigs with one of the main Xilver team a couple of years ago while he was getting the project together - very interesting. Link to comment Share on other sites More sharing options...
peter Posted May 7, 2003 Share Posted May 7, 2003 Feel free to quote me - if you want to use anyone elses comments, make sure you PM them first. Cheers Peter PS: Good luck with the dissertation - I wrote a research project for Physics A-level on LED and Tungsten lighting - I can forward you a copy if you email me. Link to comment Share on other sites More sharing options...
Peter Russell Posted May 7, 2003 Share Posted May 7, 2003 LED fixtures are already used quite a lot in television and concerts, the Pulsar Chroma Bank has nearly completetly taken over from howie battens etc. and LED walls are used for most big screen applications rather than video walls.Peter Link to comment Share on other sites More sharing options...
Ben Posted May 7, 2003 Share Posted May 7, 2003 joseph has a load of LEDs and I have been told they work well and are a god send when it comes to the lack of changing lamps etc Link to comment Share on other sites More sharing options...
Ben... Posted May 7, 2003 Share Posted May 7, 2003 Another advantage of LEDs; solid state (no moving parts) colour changers are possible - I believe the pixel-pars do this. And the 90% drop in power consumption means that dimmer city and 64A cable are probably on the way out (in the long term.) Link to comment Share on other sites More sharing options...
peter Posted May 7, 2003 Share Posted May 7, 2003 The Thomas PixelLine 1044's have a 16A in and link through, so its not the end of ceeforms... just the end of multicores :D Link to comment Share on other sites More sharing options...
tonymaslen Posted May 7, 2003 Author Share Posted May 7, 2003 will manufactures be looking into creating a focus device for LEDs or will we be left with simply a colour wash only devices. Link to comment Share on other sites More sharing options...
NickLee Posted May 7, 2003 Share Posted May 7, 2003 I'm sure it'd be easy enough to create the appropriate lens mechanism once the LEDs themselves are bright enough.My question is this: why does LED light over tungsten light dropoff in terms of brightness over short distances? n. Link to comment Share on other sites More sharing options...
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