How do you make a car rim glow without melting the tyre? Patrick Llewelyn-Davies does it with light, and thereby creates an unusually enlightening picture of this everyday object. His Light Revolution System redefines the contrast of light and shadow, as it uniformly irradiates the object from a complete circular path. A precision motor from FAULHABER ensures the uniform movement of the lamps and exact adherence to 360 degrees.
Most photographs have the snapshot noise in common: whether a smartphone selfie or an artistic professional photograph – the shutter allows the light to pass through the aperture for just a fraction of a second. Fittingly, the analog shutter noise is even simulated by fully digital cameras to acoustically mark the brief moment in which the image is captured.
But there is also a long tradition of light painting, in which the aperture remains open for an extended period of time and moving lights leave their trace on the negative or image sensor. Fascinating images and views can be created using this technique. A familiar example is the red and white streaks of light from headlights and tail lights that can be seen on long-exposure images of motorways at night. Unlike with “normal” photography, movement is not stopped, but rather captured.
British photographer Patrick Llewelyn-Davies bridges the gap between “moving” light painting and still life. In his images, the resting object is at the centre, and he uses the moving light like a pen for colouring in. Only that he adds no additional colour to his images. Instead, he causes the objects to glow and illuminate. His use of light also allows for the creation of new and sometimes X-ray-like glimpses into the photographed objects. They take on a quasi three dimensional plasticity even though they never optically leave the 2D world.
The secret to the light-painted still lives is a seemingly simple apparatus called “Light Revolution System”, which has two meanings. Revolution here means both rotation as well as a fundamental renewal. Two intensely bright LED lights complete a cycle around a round table on which the object of the photographic efforts has been placed. It generally takes six seconds for them to complete their rotation. The time can be varied, however, depending on the desired light effect. The system does not just travel a round path but rather opens completely new possibilities for photographic image composition – there has never before been anything like it on the market.
The lights are fastened to two arms and can be adjusted in height to achieve different angles of incidence. The arms are firmly attached to the rotating central axis. At first glance, this arrangement does not call for any spectacular technology, but in detail, maximum precision and extremely smooth operation are decisive. “Any pause or jerk in the rotation, regardless of how short, would result in uneven illumination,” explains Patrick Llewelyn-Davies. “There would be brighter and darker patches that would affect or destroy the intended effect. The same applies for travelling the complete circle. The arms must not move one degree more or less than 360 degrees. And they should accomplish this in precisely the specified amount of time.”
The inventor/photographer reports of earlier attempts with simpler components that were not able to meet these requirements. The greatest challenge was in moving the central axis of the system both very precisely as well as jerk-free. At the same time, the portable device needed to be as light as possible. When making the selection of the right drive, the experts of the British FAULHABER sales partner EMS provided assistance. “The support from EMS was great,” explains Patrick Llewelyn-Davies. “They provided the necessary technical expertise for the drive and the controller. It is decisive for the high quality of the product. Moreover, motors from FAULHABER have proven themselves in highly critical areas such as aerospace. That’s how I knew that they would have the accuracy and reliability required by the Light Revolution System.”
The experts from EMS identified the brushless motors of the BX4 series as the optimum solution. They were able to ensure the desired precision and repeatability of the sequence. “Once we selected a motor family, we could try different sizes without intervening in the programming”, explains Dave Walsha, Commercial Development Officer at EMS, with regard to the joint development work. “As a result, we were able to respond very flexibly to changes to the system.” Thanks to the compact and lightweight design of the BX4 motors, the “ideal weight” was also maintained.
Of course, the photographer thoroughly tested his Light Revolution System himself. In his online gallery, you can admire examples of the unique light effects that he has achieved with his system. The “glow” that he elicits from unassuming everyday objects like a chicken egg or a fishhook is created by placing the circling LED lamps very low above the table. Because part of the light is laterally reflected by the objects onto the base, a glowing aura is created that appears to emanate from within the objects.
The system is currently being tested in various application areas. Instead of the lights, a camera can also be attached to one of the arms. If it is attached to an arc-shaped arm, the object can be photographed at a uniform distance from various angles. This method is used, e.g., by museums to calculate high-resolution 3D models of their valuable objects from image data. Researchers can then exchange this data worldwide and use it for their studies. Furthermore, precise replicas can be created using 3D printing. “Up to now, a considerable amount of hand work was associated with the creation of such images,” says Patrick Llewelyn-Davies. “With the Light Revolution System, the process can be largely automated and greatly accelerated.”
Exposure technique (faulhaber.com) https://www.faulhaber.com/en/markets/optics-photonics/exposure-technique/