Image: Reto Togni

“This image is like a cat biting its own tail. It’s confusing”, says Reto Togni. That’s precisely why he likes it. He is doing his doctorate in design and is a kind of in-house photographer for the Laboratory for Movement Biomechanics at ETH Zurich. “This isn’t a moving walkway. It’s a fluoroscope. It’s a kind of X-ray machine that makes videos – 30 images per second”. He has arranged six individual photos so that it looks like a conveyor belt with six fluoroscopes on it.

But it’s not just the photo that’s a little bit crazy – so is the machine featured in it. This is the world’s only mobile fluoroscope, and it can move in front of its test subject, even down a series of steps or a ramp. It’s situated in the crest of the white semicircle you can see here. The biomechanist Barbara Postolka and her fellow researchers use it to understand the movement of the knee better. This lets them optimise implants. In this picture, Postolka demonstrates the machine herself. “In X-ray videos, we can observe the bones”, she says. “The black dots on my body are also recorded by 22 infrared cameras. This means we can also capture movement in space”.

Depicting the fluoroscope and Postolka’s movements as a serial picture is similar to the old technique of chronophotography, in which movement was depicted by means of many still images taken shortly after each other. Essentially, that’s also just what X-ray videos do. “All motion analysis today – such as in sports – is based on the selfsame principle”, says Togni. This is why it seemed apt for him to submit this project to the SNSF Scientific Image Competition. “The image should have an infographic impact. That’s why I chose this very strict side perspective, in which the lines and surfaces are as straight as possible”. The result is an interplay of clarity and confusion that together make the image so attractive.