RGB battens for internally lighting perspex pillars

[Barney]

Hi BR,

 

On my next show, I've been asked to light 4 perspex pilllars as part of the set. These are 14' high, with opaque perspex to three sides, and need to be RGB(A?) colour mixable from the lighting desk. I'm yet to find out about rigging possibilities for fixtures mounted within the pillars, but let's assume that it will be possible.

 

My first thought was to use a number of LED battens mounted vertically, as a continuous strip fixed to the rear of the pillars. Some frost or silk might be needed to help spread the beam angle - I'm assuming that the pillars are likely to be around 30-40cm square.

 

Given the height of the pillars, I would probably need 5 typical LED batten units per pillar. However, the cost for hiring such units is coming in at around £1400 for the two week run.

 

So my question is, is there a cheaper and/or better way to do this?

 

Ideally, I would like a solution that lets me control a number of RGB cells per batten, allowing for some nice rainbow colour 'fall' effects down each pillar, rather than a continuous solid colour per batten. However, beggars can't be choosers.

 

I don't really want to use backlight from the rig, as the pillars are likely to be moved around the stage.

 

All ideas and comments considered!

 

 

Thanks in advance for your thoughts,

Barney

[peza2010]

I cant recommend fixtures, but a slight warning... If your looking to get smoothly lit pillars, without being able to see the individual leds your gonna run into a bit of trouble. The amount of frost or silk required to.make it smooth kills a hell of a lot of output. I have had good results with a led can both top and bottom, however these were cylindrical pillars.

 

If smooth isnt a problem, you wont have much trouble

[Barney]

Thanks Peza,

 

The pillars are going to be frosted, opaque, perspex, so hopefully this will help diffuse the light and make individual LED 'cells' less obvious.

 

However, the brief is for single solid colours, so this shouldn't be too much of a problem for smooth lighting. Changing the colours down the pillar was just my artistic side thinking of the potential possibilities :)

 

I did think of LED cans top and bottom but, given the 14' height of the pillars, I think you'll end up with a bright spot top and bottom, but nothing (less) in the middle?

 

 

Cheers for the comments though,

Barney

 

 

As a general comment, I should also clarify, this is an amateur show - so not a limitless lighting budget for this particular effect...

[dbuckley]

My experience of using LED battens is limited to dirt cheap Chinese jobbies (these, link may not last well) which are each about a metre long, and are split into three chunks, with independent RGB control of each third, and certainly with a few of them you can do pretty rainbow effects.

 

The problem you are likely to face is that as your opaque surface is close to the bars (400mm at best), and that the LEDs have a fairly narrow beam width, you wont get a nicely illuminated column on all sides, but a bright line of colour. Even with a couple of metres of throw you still get a fairly defined line, albeit with soft edges. You would need enormous amounts of diffusion to get "smooth" illumination.

 

LED strips might do the job, the standard RGB strips make my kitchen worktop pretty colours (but sadly not a great white) from the under-cupboard lights, but its not an off-the-shelf solution; a lot of assembly required. There's also a question of output, how bright do these columns need to be...

[gordontech]

You must be renting from the wrong people for that kind of price for basic RGB battens.

 

 

 

I have done it three ways in the past.

 

I used opaque perspex and used 3 strong (7x3w) led pars at the top and bottom, this was when punters were walking round the pillars. Looked nice (can try and find pictures if you want) and didnt have a batten seam.

 

Again opaque perspex but the bac didn't need to be seen so I mounted 3 40 degree battens on the backside of it. Might have to be choreographed a bit if your moving them around.

 

The other way wasn't as effective for a clean effect but mounting LED battens with frost in them (dropping the front off) and then doing a silk down the middle of them. Looked quite dance show(ey)

 

 

Most battens will be 20-25degree so its worth looking at this to get a better idea. The wider the spread the easier it is to fill the tube.

 

 

 

 

Hope this helps. PM me if you would like me to find plans or pictures

 

 

 

 

 

 

 

G

[rossmck]

Depending on the pillars you might be able to use an LED tape of some sort ? I've built this into a few set pieces in the past - it's easy to work with and if you're careful you could reuse it in the future.

 

For obvious reasons they aren't really available as hire stock but around 16m of RGB LED tape would cost about £300, you'll also need some appropriate controller to drive it from DMX (about £70 per unit)

 

Obviously this would be a single colour per pillar - although you can get individually addressable LED tapes they aren't (yet) cheap.

 

Alternatively I know of a couple of groups that found that buying some cheaper (Chauvet, Showtec, LEDJ etc) LED battens and selling them after the event on eBay (in as-new condition) was the way to go - much cheaper than hire, indeed I think they actually sold some of them for more than they bought them for!

 

(In the interests of full disclosure I am associated with a company which acts as a reseller for some of the above companies and provides LED Tape products, primarily for architectural installation)

[maeterlinck]

I would suggest LED tape / strip as well. Generally 120deg beam. Will weigh less than batten as well. Probably run cooler. You could easily split the sections on the piller to gain the band control you want.

 

I do a lot of this sort of work so feel free to PM me if some non-forum help would be useful.

[Ynot]

I'm going to go against the grain in this thread and suggest that once you have your pillars you simply experiment with LED PAR type fixtures. Certainly some of the more recent lanterns give a far brighter level of light and so I think you'd be better to revert to your original thought of one top, one bottom. And you could well be surprised with the results. I'd say that you will really struggle to get an even coverage from battens or strips, as neither will likely have too wide a beam angle for this sort of job.

 

OK, you will probably have SOME slightly dimmer area in the middle of the pillars, but it won't be nil, even at 14'.

 

Just make sure that when the pillar size is spec'd that you allow enough space at top & bottom for the LED to be mounted, and for cable entry to the lantern.

 

 

[DonkiDonki]

I would also consider the par top & bottom option. With a bright fixture with a narrow beam angle you should get acceptable results. If you can find them, the revised version of the James Thomas P90(PixelPar) would be a good choice; they have a nice 10degree beam and the new version is almost twice as bright as the original. Even the original P90 would do it though that is only RGB while the newer PixelPar is available as RGBA or RGBW.

 

Most of the recent alternatives I've encountered have had a much wider beam angle, but I'm sure some of the members may know of suitable models?

 

Something to check with the people building the pillars is if they intend to have any kind of ribs or bracing which may cause you shadowing issues.

[musht]

Choice of frosted acrylic will make a difference, frosted ,sometimes called obscured in glass, is different from opaque which would allow no light through.

 

Perspex is trade name for one maker of acrylic sheet, there are quite a few competitors with different products.Local signmakers or plastic stockholders probably worth talking to,especially for the quantity of sheet your thinking of using and joining.

 

LED tape probably need multiple runs against high ambient or wide columns.

 

Mebbe also consider , inflated or stretched spandex columns that will take light well but easier to handle and cheaper than solid acrylics?

 

Commercial disclaimer, also available for quotes via pm ;-)

[gordontech]

The LED's I used at the top/bottom of the pillars were showtec LEDtri7's if that helps

 

 

 

 

 

G

[rossmck]

The LED's I used at the top/bottom of the pillars were showtec LEDtri7's if that helps

 

I've also used the Showtec Compact Par 7 Tri / Chauvet SlimPAR 7 in a similar application and worked quite well. If budget stretches to it I'd consider the "Compact Par 18 Tri" if possible if the dimming is important as it's far smoother at the lower end than the Par 7 Tri.

 

[Barney]

Thanks for the comments.

 

I did look at LED tapes, and have got a quote for the necessary bits and pieces, however it is the intensity I'm worried about. I have been quoted a lumens figure for 'white', but am not sure that this approach will be bright enough to cut it for more saturated colours.

 

Good call with the buy/re-sale idea: that's worth considering. Anyone in the market for 20 lightly-used LED battens or 20 metres of LED tape plus PSU ;)

 

The LED cans top and bottom may be the most viable option, but I'm waiting for pictures of the pillars/construction/bracing before I can decide.

 

pedant

Ok, I didn't mean opaque, I meant translucent, but you got the general dea ;)

/pedant

[tom_the_LD]

In terms of LED tape type things, White Light stock "X Flex" LED strip which comes in 5m. It's RGB but I'm afraid I don't know how it gets divided up for control purposes - aka whether it's one colour per strip or whether you can get control of the individual LED's.

[stevep]

Did something not wildly dissimilar but flooding white panels with light from the front.

 

We acheived it with LED Pars - in particular because it was at close range we used Pars which had 12 individual LEDs for each R G and B - this meant that fading between the colours created a bit of movement. With a PAR top and bottom we got some decent effects.

 

We also tried the LEDJ stratos wash panels - as they have a 120 degree beam, but which due to having larger numbers of 10mm LEDs gave a much smoother effect over the column but lost the movement.

 

I'm surprised at the price you're being quoted - might be worth telling them what you're wanting to achieve and ask for cheaper options as they'll know what their hire stock is capable of. Finally if the pillars are mobile enough ask if you can take one round to them or get a small number lanterns on hire for an afternoon to try them out on one pillar.