Tuesday, September 10, 2013

A cheap lightbox for photographing small objects without shadows

Last week, I decided to make a lightbox for the lab. Not the kind where you have lighting from below to look at negatives or slides, but the kind which can light an object from all sides, so that you can get clear photographs.

To do this, I bought a white LED strip and a transformer from the local hardware shop for R400. The LED strip is backed with adhesive, and all the LEDs are connected in parallel, in groups of 3.
The reel with the backing strip covering the adhesive.
The leftover lighting strip still on the reel

The LEDs are connected in parallel in groups of 3
This means that you can cut the strip at any point between two groups of three LEDs, and it will still work. Also, if any one LED fails, the rest of the strip still works.  This is what a working unit of three LEDs looks like:

Unlit, on my laptop keyboard for scale

All lit up!
This made the construction of the lightbox trivially easy: Cut a small hole in the side of a plastic box; feed the cable through the hole; stick the lighting strip in a spiral around the inside of the box; connect the contacts to the transformer, and cut a large hole in the base of the box for the camera lens to poke through (OK, that was a bit of a cosmetic failure, because the plastic shattered while I was cutting it. Clumsy!)

Here is the completed lightbox: you'll see that I put some paper inside it, so that there would be no harsh reflections from the LEDs.


Here's a picture of some shiny candy taken with and without the paper diffuser:


The effect with all those little lights is quite pretty, but it can be distracting.  Also, the complete absence of shadows is a bit strange.  I'll have to experiment with casting intentional shadows (e.g. a black piece of paper at one side of the lightbox?) and with different backgrounds (a 1 cm grid for size reference? a solid black background?)

The light is pretty close to a neutral white: I didn't actually measure the spectrum, but because it's not identical to daylight or fluorescent light, I used a white sheet of paper to set my camera's white balance before taking pictures.

Finally, here's a test picture I took of the previous Chocolate Eclairs packaging (because I had one lying around):
If you look closely, you'll see that the background that I used was a piece of paper with printing on the reverse side: lazy, I know!  Still, I got a well-lit picture with light coming in from all sides. Proof of concept done!