Light source for DIY light box

[Blaize110]

At the moment I am building myself a single panel light box using a 3 channel colour organ (so 3 colours of bulb) with dimensions 1x0.6m. However I am not sure what to use for the bulbs (they need to be 12V). The 2 options I have come up with so far are many Miniature LED lamps or some 12V dichroic bulbs. Both have their disadvantages. I would need a large quantity of LEDs to create a substantial brightness, however the filament bulbs may create a heat problem and I dont want them melting the acrylic in the front of the box.

 

What do people think? Perhaps someone else has made a similar light box and can advise me.

 

Thanks

Rory

[Jram]

I built a lightbox for a friend a few years ago. It stands about a metre tall, 60cm wide, and about 18cm deep. The front was an offcut of clear perspex, backed with frost and some blue gel. Inside I fitted three of the small connectable strip lights you get for undershelf lighting applications and the like. It worked out not badly for a first attempt, although even with the frost you could still tell there were three separate light sources inside.

[Blaize110]

I think ill buy a few filament bulbs and experiment with some offcuts of acrylic. If they work then the next decision will be how many should I use per channel to cover the 0.33x0.6m sections. Again, some experimenting when my translucant acrylic arrvies may be in order.

[Joe White]

Ive been making up L.E.D panels to replace the single 15w lamp in my existing light boxes, I only require 10 LEDs per section and the sections are quite large. I'm Using Super Flux LED's 5mm head version.

They work extremely well especially if you use fine sandpaper too rub a bit off the top of the LEDs off. Joe

[Blaize110]

Thanks for the tip. I am currently testing some 20W dichroic bulbs infront of some acrylic to see if it melts. Quite a lot of white light spillage out of the back of the light though!

 

EDIT: Typo

 

ADDITION:

After running the dichroic for a good few hours I have come to the conclusion that even if the acrylic didnt melt, the base of the bulb would get very hot and a load of hot things in an enclosed area made of wood might not be the best idea. I also dont like all the light spillage. I guess its LEDs then...

[mutley]

Another alternative would be small cold cathode fluorescent kits such as those fitted under chav's cars or in PCs. At less than £3 for two 12" tubes, and the 12V inverter module, it could work out cheaper than LEDs. example

[Ekij]

I'd recommend LEDs, they have a number of advantages

1. A lot cooler than the alternatives

2. The fact that you need a lot of LEDs is better in this application as you can divide them more evenly.

3. Long life.

 

They are also potentially easier to dim as they maintain this colour temperature at lower outputs (you don't need a dimmer curve that compensates for a cool incandescent being redder).