The experiment is part of the gallery’s Making Colour exhibition, which uses scientific methods to demonstrate artists’ use of colour and how they created the colours in their paintings.
The lighting experiment looks at the way the eye and brain respond to colour under different lighting conditions, and how this affects people’s perception of artworks. It uses computer-controlled LEDs operating at varying wavelengths to simulate different lighting environments, such as candlelight.
Members of the public watch the effect of the changing light on a painting and indicate their preferred lighting. The experiment also tests their perception of the colours as the lighting changes.
The experiment was developed in conjunction with Professor Anya Hurlbert, professor of visual neuroscience at the University of Newcastle, who will analyse the results. Making Colour opened at the National Gallery in June and runs until 7 September.
The findings will be used to help improve the viewing experience of the public by adjusting the gallery’s illumination to suit particular paintings. Joe Padfield, a conservation scientist and lighting specialist at the National Gallery, told BBC Radio 4’s Inside Science: ‘If you have an exhibition looking at very old paintings that were always constructed using candlelight or daylight, you may want some kind of combination of both. If you have more modern paintings that were done under tungsten light or fluorescent, you may want to change the light.’
He believes that tunable lighting is the key, since it would be costly and unfeasible to install new lighting for each exhibition.
The National Gallery has been converting its former tungsten lighting to LEDs for the last few years. In addition to energy-saving benefits, LED lighting has a significant advantage over tungsten: the colour temperature does not change when it dims.
The gallery has installed an automated system that activates the LED lighting in small increments according to the level of daylight coming through the many skylights. The goal is to ensure a consistent viewing experience for visitors as they walk round the galleries, regardless of the ebb and flow of sunlight.