Ready? Let’s get stuck in and not waste time.
No, it’s not some kind of digital art – this is a photo straight out of my camera. You might have encountered similar photos before. Here’s one more, then I’ll tell you how it’s done.
OK, here’s the trick. They’re water drops on a CD. The mirrored and layered properties of the CD surface reflect and interfere with the light hitting it, creating an intense rainbow. But anyone can see rainbows on a CD, and they’re not always as intense and smooth as the ones you can see in the pictures. What’s the secret?
I’m not quite sure! I was shooting with a point and shoot, very close to the CD surface, with a large flourescent light behind it. I think the diffuse yet bright light, combined with the extreme closeness of the camera to the CD surface, created the effect. It was very dependent on the angle of the camera relative to the CD and light source.
The other trick is making the images from water drops. Clearly, you can’t just spray them willy-nilly, or even use a dropper.
The technique works because of the surface tension of the water. I had a cup of water and a set of wooden toothpicks, which I’d modified to range from thin to thick. I’d dip the toothpick in the water and touch it to the surface of the CD. Some of the water would stay on the CD.
The surface tension of the water is caused by the attraction of the molecules in the liquid to each other. The ones on the outside of the drop are pulled inwards by the rest of the molecules, so the drop tends to form a spherical shape.
The challenge is that, with very small water drops, evaporation gets rid of them very quickly. So I had to come up with the simplest possible concept for representing the image I wanted to ‘paint’, then execute it with the toothpicks. It was a fun night of testing; here’s a collection of the final results:
So now you know. You need a CD, toothpick, some water, a light and a camera with a macro function. What are you waiting for?