A new, fully automated, fine art infrared scanning system isn’t just a prime example of what modern technology can achieve. It also shows how a scientific tool with micron positioning accuracy can be created from standard industrial automation components. The system is the brainchild of motion control specialist, SmartDrive®. Working in league with the linear motion company, HepcoMotion®, it has optimised the process of infrared scanning, greatly extending the scope of the technology. And the benefits of the system aren’t confined to infrared. The system control and specifically developed image stitching software also enables distortion-free digital photographs of large works to be taken for further study and record. For the art conservation world this system represents a significant imaging breakthrough.
The SmartDrive system is called SatScan and as its name implies the technology mimics that used in mapping systems with the optics ‘flying’ over or across the subject. Imagine zooming around Manhattan in Google Earth. What you see are the square roof tops, no shear sides of adjacent buildings. This is because small images are taken from a perpendicular position and then stitched. SatScan works in a similar way by moving digital and infrared camera heads incrementally around the artwork using encoder technology to achieve precision positioning.
“We know the position of the carriage to within ±1 micron,” explains the system’s designer, Dennis Murphy, Managing Director of SmartDrive. “We’re achieving this from automation components with industrial tolerances of 100 – 200 microns. In scientific terms we are also using relatively low resolution, off-the-shelf cameras. But by acquiring a small field of view – maybe just an inch or two square – and holding it perpendicular to the painting we can take images that are completely distortion free.”
The first large scale SatScan is installed at the Hamilton Kerr Institute near Cambridge, a centre of excellence for conservation services that is world renowned for its work on tempura easel paintings. It provided the expert knowledge needed for the art version of the SatScan development and is now using the system on a daily basis. Infrared imaging is just one of a range of tools used by the Institute’s conservators and is primarily used to see any under-drawings on the canvas or to examine previous re-touching. For example it will show if an egg tempura painting has been retouched with oils.