I've been asked to build an A3 size lightbox by a lady who is doing a botanical art course and has need of such for tracing leaf shapes and the likes onto paper.
I can get what is billed as suitable opaque perspex off Ebay - A3 and 5mm thick - I'm wondering if a suitable light source would be part of one of those strings of LED's at around a fiver for 5m.
Rob
The traditional way would be 2-4 tubes.
I would argue that this is a good way to go as:
a) You can buy tubes with excellent CRI and the right colour temperature;
b) It's maintainable - light gets poor, change tube :)
As you can mount the control gear next to the tubes in the box, it can be all quite neat :)
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What colour balance is required? LEDS might not be suitable.
When I built a similar thing I found it was best to have the LEDS pointing backwards at crinkled up bacofoil. This diffused the light very nicely.
Bill
Colour balance is not important. My friend writes "It is for transferring initial drawing onto watercolour paper and is only faint lining for giving plant outlines etc."
I'll give the LED's a try as they aren't going to break the bank. The bacofoil idae is good - thanks.
Rob
Do remember that an A3 light box is only about £66-£65 when considering how to make one.
...
I read the title as 'has anyone built a lighthouse' and thought that is an impressive DIY project :-)
Most of the ones I've seen have used fluorescent tubes with a specific type of phosphor that is colour neutral. However for the use its going to be put to, this might not matter, and neither might the variation in intensity. Brian
You could use a strip of RGB led's and a colour mixer controller, then you can set any colour tone you want,
Reminds me of a use i could have had for an old tv.... one of those awfull DMTech 42 inch jobbies, one of the boards had gone resulting in weird colours, and incompetent tv bodger (not fit to be classed as an engineer as they don't even know which way to hold a soldering iron nowadays) cracked the lcd panel i the process of replacing boards,
new tv bought on the payout, old un left for us to bin,
So i removed the lcd panel, and was left with a nice opaque white flat panel with about 8 long CCFL tubes giving an even light, all housed in a 'frame' i thought at the time i'd use it to make an illuminated sign for my games room, but never bothered and chucked it out when i got fed up of having to move it when searching for stuff,
Would have made an ideal light box.... mind, just displaying a white screen on any TV/laptop/tablet could do the same i guess.
why not buy frosted glass in glaziers - be much better, and won't flex. I built a dummy window in the WC this way ...
So when you use said room, it looks like a window to outside with diffused light ... also makes room seem much bigger.
I used 2 tube strip lights (15W I think .. whatever TLC carry) and mounted them behind a stip of ply so the tubes can't be seen directly the back of 'box' I coated with crinkled up kitchen foil .... light bounces off that in random manner .. works well for effect I wanted.
In similar vein, just stick the leaves to a window and the paper on top and use the daylight. to trace the veins.
Especially if his name had been Stephenson:
I doubt if 5mm A3 perspex will be rigid enough for tracing on unless you put extra support under it. Be OK for looking at big transparencies.
5mm frosted glass would be a a lot stiffer.
He needs to be careful what he buys..
opaque doesn't let light through. translucent lets light through but is diffuse in some way like obscure glass or frosted glass. clear is just window stuff.
You can buy toughened glass shelves in Ikea about 550 mm square for about £12 and put some tracing paper under it to make the top of a light box. It would be best to space the paper away from the top by an inch or so.
They were being sold off on ebay for peanuts a couple of years ago as graphic arts houses/ ad agencies were disposing of all their old transparency viewing kit. There will likely be some still kicking around if you have a look. Cheapest way for me, should I need one, is to use a 2ft square office ceiling light and put a sheet of translucent plastic over it.
Thank you! I've been resisting the temptation...!
You could make frosted glass at home by acid etching, could be messy chemicals though. Alternative is to buy frosted glass at glaziers - cheap enough.
look up the MSDS for hydrofluric acid , not a kitchen table operation...
Etch effect window film is available in all sorts of types but for a lightbox want opalescent , milky, there are a couple of grades specifically intended for lightbox use,
Another alternative, if you have some clear perspex, is to make that frosted using finest grade wet-and-dry paper used wet. Use an even circular motion until the area concerned is all rubbed down, wash with a drop of detergent, dry, and check for even coverage. Repeat if necessary....
Charles F
Done that in the past then discovered this:
For the OP they have a branch in Grangemouth.
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