Light is the connection between objects and human beings and it assures visual perception. Changing light the colours and the feeling of paintings change. In these years there is a great revolution in the lighting market, new lighting sources are developed and they allow sophisticated and innovative solutions. The research for LED obtained important and exceptional results offering new technologies able to open new lighting scenes. This new lighting source offers many advantages and also a wide variety of different lighting spectrum not expected in the past years. To find the best light it is important every time but it is fundamental speaking of visual art. Light in fact is able to interfere on conservatory aspects and to change colours and the final visual effect of artworks.
To investigate how the perception of paintings changes with light the National Institute of optics of the National Research Council Ino Cnr developed a specific research. Three important paintings ware selected and exposed in the Ino Cnr laboratory inside the Opificio delle Pietre Dure in Florence, one of the main institution for restoration of artworks in Italy. The paintings were different for historical period and subject. They were “Memory of light” by Giovanna Rasario (Figure above), ‘Saint Agostino’s study’ by Sandro Botticelli (Figure on the right) and ‘Portrait of woman’ by anonymous (Figure below).
These paintings ware lighted with different kind of LED lighting sources: Ra 84 3000K and 4000K, Ra 98 3000K and 4000K, Ra 92 3500K and 4200K.
For the test 25 people were invited (9 man and 16 women) with ages between 23 and 60 years old and with no problem for colour vision. Between this group five of them were experts in art the others had general professional skills.
In the photos below it is possible to visualize that colour perception changes with light.
People were invited to say their preferences about the colour perception.
The first results of the experiment gave evidence of the inadequacy of the actual system to calculate the parameter Colour Rendering Index in the characterization of LED sources. During the experiment the preference were for lighting sources with Ra 84 and not Ra 98 as expected. There is also a preference for lighting sources with more ‘red’ inside the spectrum and this is true especially for the figurative paintings because the incarnate and other details were more impressive.
Elisabetta Baldanzi is a physicist of the National Institute of Optics of the National Research Council INO CNR based in Florence, Italy. She was graduated at the University of Pisa and she is Contract Professor at the University of Florence, degree in Optics and Optometry course Optics for Vision. Her research is focused on psychophysics of vision and lighting technologies. She is also the responsible for the scientific communication of INO CNR.
Alessandro Farini is is the head researcher of the Visual Ergonomy Lab at the CNR-National Institute of Optics in Florence, Italy. He is a physicist graduated at the University of Florence, where he also received PhD in Optics. Alessandro Farini is also Contract Professor at the University of Florence, degree in Optics and Optometry: he is teaching Photophysics of vision and Psychophysics. Prof. Farini’s research work is addressed to the study of lighting and ophthalmic optics.