Friday, June 20, 2008

How to built a lightbox

When I started working with the polymer- or solarplates last spring, I figured it would be the cheapest option just to build one. Since there was some trial and error, I figured I would share how I built the one we are using at school now.

The hardest part was figuring out the lights, since there are limited resources here in the "country". (I live about an hour out of Savannah, GA) If you are only going to do smaller plates and have the resources to buy one, get a facial tanning lightunit from ebay or from a supplier. Solarplates need UV light to expose, so the tanning units work great. Then all you do is just build a box around that. Note, regular fluorescent lightbulbs won't work.

I wanted to make a little bit of a bigger unit, to accomodate larger plates, so I built one out of MDF to house two- two lightbulb- ballasts. (total of 4 bulbs) The cost ended up being about $100 for everything.

Shopping list:


4- 2' blacklights that you can get from your home improvement store or even at Walmart

2- 2 bulb ballasts (Lowes)

Some screws and wood glue

2 hinges

Above. Here is a picture of the finished box with dimensions. I did not wire the cords from the two units together so you have to plug them in separately for now. Addition: You can plug the cords into a surge protector, which makes using them easy, since it has a switch on it.
Below. A picture from the inside of the box

A picture of the sides, the little strips are to make carrying easier. If yo plan on using the unit a lot, you might want to drill a couple of holes on the sides to let some of the heat out.

With this unit, the lights are about 8" away from the plate, and we have tested exposure to be 1 min 30 sec. For aquatint screens we have been doing about 1 min 10 sec first with the screen, then the same amount of time with the image.

Hope this is helpful to you. If you have any questions, please ask.


Tootsietails said...

Is there anyway you could add a vacuum to it so it holds the negative close to the plate on photo polymer plates?

Mirka Hokkanen said...

I am sure you could with a lot more effort. You could probably build a holow box and drill holes in it. It would work like a vacuum table for screen printing. But just using a thick piece of glass and a sturdy backboard is much much easier. You can add a piece of thin foam in between too to help with the film laying flat.

Heather Jacks said...

Hello, I also built a light box with four looks very similar to yours. I am having a very difficult time with exposure times. I can achieve good results with the sun, but not yet with the box. What wattage bulbs are you using in your box? If I expose for a shorter time like you recommend, the plate is sticky and pink comes off during the phone book drying, and wont hold ink. If I expose for a longer time, the plate seems not to have much detail. Any advice you could give would be much appreciated. Maybe I am greatly overexposing in the box...but if the plate is sticky, it seems to me I need a linger exposure. The plates are expensive!

Mirka Hokkanen said...

Hi, thanks for your comment. I don't have that box anymore. I sold it when we moved to Germany and the voltage is different here. They were just the regular bulbs I got from Lowes or Home Depot. If your plate is that sticky when you are drying it, it seems you need to change the way you are cleaning it out in the water after exposure. It sounds you need wash out more/change water temp so there is no more pink stuff coming off when you go to dry. You did not explain anything about how you wash out, so I can't help you there much more.