Light Diffuser

Peter Cook

I am in the process of replacing halogen GU and MR bulbs with LED units. 5-7 watts instead of 50 for similar lumen output.

I also want to eliminate the reflections I get off this office keyboard from a ceiling downlighter and off dinner plates in the kitchen from a spot mounting. LEDs seem to have a narrower beam, which makes the problem worse. Moving the lamps is not an option, so I have done a bit of searching for a proprietary solution, so far in vain. I could get opal discs of polycarbonate cut and then work out a method of mounting them, but it is hard to judge if this would cut out too much light as well as the reflection. The obvious answer I thought would be to get some ‘spun’ glass, so familiar when working, and experiment. So far Google has failed me but I suspect that I would have to buy a quantity far in excess of my requirement.

Have any of you encountered this problem and found a solution? Or do you know of a supplier where I might get a small quantity (a sample maybe) of glass fibre spun? 

Dave Plowman

It’s a common problems with some types of LED. Viewed directly, they are
much brighter than the light they cast into the room, compared to tungsten.

Chris Woolf 

Led spots can be had with a range of angles, just like the halogens.

Glass fibre not bonded in a resin matrix is going out of favour like asbestos, and with good reason. 

Given the cool running of the LEDs, maybe just use some frost gel? 

Peter Cook

That is an idea. Do you think that gel would stay in place with say double sided tape?

Terry Meadowcroft

Maybe worth thinking about using flat LED panels? I have just installed two 2 foot square mains powered flat panels on back and front hallway ceilings, powered by the original ceiling light fittings (bayonet mains plugs are still available), and the light from them, mounted flat to the ceiling and automatically tripped with movement censors, is beautiful; similar to the light from a window, which was the desired effect. The light is very diffuse and clean and maybe smaller panels may be available.

Just a thought outside the box. 

Peter Cook

Thanks for the thought! It was worth considering but the problem kitchen lamp is one of seven and the other six are fine. I have low ceilings with exposed beams. One of the beams is directly above the table where the reflection is a nuisance and a panel light would need to be so close to it that it would cast a shadow. Also the panels available seem to be 500 mm square 40w and give out 3400 lumens. I am looking for about 400 lumens consuming 5 or 6w. If I can find a more frosted GU 10 than the one I am using that might do the trick, otherwise I must try to track down some adequately frosted gel.

Clive Gulliver

Would the frost gel as used in studio lighting be any good?

Ian Hillson

You could try a manufacturer direct (Rosco are in Bromley http://emea.rosco.com/en and Lee in Andover http://www.leefilters.com/): give them a ring and they may pop some A4 size samples in an envelope if you say you worked in telly and sound as though you know what you’re talking about. 

If you’re ceilings are low and you have beams then get a long LED fitting, screw to beam but point it at the ceiling – assuming your ceilings are painted white that is. For more oomph then paint that bit of ceiling with aluminium paint!

Peter Hider

Re: I have just installed two 2 foot square mains powered flat panels

How did you fix the light panels to the ceiling as presumably you have a room above and joists crossing the panel location. I want to install one in our kitchen which is quite dark at one end.

Terry Meadowcroft

The trick was to keep the existing cable to bayonet fitting in case I have, or whichever of my family outlives me has, to remove my eccentricities and sell the house. I have attached two short battens, deeper than the bayonet plug-and-sockets, one at either side of the original fitting, to the ceiling, and let in and glued to these battens are pairs of those lovely little rare earth disc magnets, each pair facing N and S toward the fitting.

The cables of the fittings are fitted up with bayonet plugs and plugged into the existing bayonet light fittings, and the panels, whose backs are made from steel sheet, are offered to, and eagerly taken up by, the magnets. The bayonets and cables sit betwixt the battens. The panel can be moved to line it up.

Hey, presto!

Peter Hider

I’ve just replaced my halogen recessed bulbs in my kitchen with OVIA (maker’s name) 50 watt warm white dimmable OVLA1003W5Ds. I was surprised how closely they performed in spread and luminance to the halogens. The beam is quite well spread and may solve your reflection problems.

The website for the manufacturers is SCOLMORE.COM. I got them in Byfleet at an electrical wholesalers at about £6 each.

 

ianfootersmall