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Mehr Licht…

3 November 2014

Most of the people who read this blog would be appalled if they went to the opera and were treated to amplified singing. In contrast, much popular music would have no impact if it were not projected at dangerously high decibel levels. Some draw an inference from this I don’t need to spell out.

Those of you watching the new film on J. M. W. Turner may be aware of a classic monograph entitled Colour in Turner. What interests me in this piece is Colour on Turner – or for that matter, on any work of art, particularly in museums and temporary exhibitions.

We take for granted the need physically to be able to see pictures, and the requirement for them therefore to be lit – often artificially, particularly in gloomy, overcast England – is usually overlooked. Those of us who are interested in old master drawings will be more familiar with the issues: faded watercolours on bleached paper simply don’t have the impact of shiny, newly varnished oil paintings, and so we grudgingly accept that exhibition duration and viewing conditions have to be controlled. This is particularly harsh on the elderly whose sight struggles to accommodate to low light levels. And most of us are dimly aware of lux and lumens. But that’s about it.

It is a matter of fundamental physics that each time you view something, energy has to hit the object. Normally the levels of destruction are utterly insignificant, but certain objects show the signs readily enough. Even some pigments in oil painting suffer: Reynolds’s Countess of Albemarle saw a ghost after her death, not in his studio (the crimson lake pigment on her cheeks was as fugitive in oil as it was in Cotes’s or Liotard’s pastels). Drawings fare worst where the paper is bleached by exposure to sunlight.

Museums have in recent years put a great deal of effort into trying to find solutions to this conundrum, and scientists and lighting manufacturers have come up with a string of solutions. Simple tungsten filament bulbs, which have been used for over a century to provide lighting for virtually all purposes, have three particular disadvantages: they are highly inefficient in terms of energy consumption; the bulbs need to be replaced regularly; and they are rather yellow in colour compared with sunlight (this is usually expressed in terms of “colour temperature” – which is a little unfortunate, since high colour temperatures look blue, which painters consider a cool colour). The tungsten–halogen bulb was a considerable advance a generation ago. But now the latest craze is the LED.

These devices are typically used with filters which allow all the energy to be concentrated into specific parts of the visible spectrum. This is great in terms of energy saving (and that means not only significant monetary savings for museums, with rapid investment payback periods, but also a significant reduction in museums’ carbon footprints, which tends to be an important part of museum directors’ scorecards – when you and I think they should be assessed on brilliant acquisitions etc.). When a curator is shown a painting illuminated with such an LED compared with one illuminated by an incandescent bulb using the same energy, the LED is likely to be preferred: more detail will be visible, and the colours will appear truer, so it is easy to see why these devices are being adopted fairly widely.

These sort of comparisons however are I believe quite dangerous. They are like climbing Escher’s staircase looking at each corner on its own, thinking you are ascending but finding when you’ve turned several corners that you are below where you started. For in many cases the results of LEDs, as we see them particularly in exhibitions, can be utterly ghastly.

It’s difficult to explain precisely why this is so without discussing spectral response curves and other technical matters, but in essence I believe there are two reasons. Firstly, LEDs typically choose to apply their energy at several (typically three) wavelengths. No doubt the three colours combine to create the illusion of white light, but the effect seems to me analogous to data compression in digital music: good enough for the casual listener, but leaving a slightly artificial sense that one can’t quite put one’s finger on.

The other, more obvious, concern is that these LEDs are used as spotlights rather than as a source of ambient lighting. This means that everything is harsher and more dramatic than in real life. For some of us old master painting is already dramatic enough without these added intrusions. It is not simply that there are dazzling reflections (e.g. the varnish on so many of the paintings in the current Rembrandt exhibition at the National Gallery), shadows on pictures where the spots are placed too low or unwanted surface textures visible in the raking light from spots placed too high. There are also issues when these lights are combined with ambient lighting of a lower temperature: some of us find the transitions physically uncomfortable.

Fundamentally I question whether the scientists haven’t simply confused the higher temperature of LEDs being closer to sunlight with a different type of fidelity. This lighting is so far from what was available to the artists or their clients that the colour contrasts could not possibly have been envisaged or intended. Of course more detail is now visible: but that is why these lights belong in the laboratory, not in the gallery.

It is easier to accept the need for such lighting in exhibitions of works on paper. But the Moroni exhibition currently at the Royal Academy raises a particular problem: the inclusion of a single drawing in one room requires the low-level lighting for the whole room which to me makes my point when compared to the rest of the exhibition. It suggests that the current vogue for mixing paintings and works on paper in the same rooms should be rethought (I’ve never been persuaded that these juxtapositions are effective anyway).

You don’t have to hear chords of G sharp minor to experience considerable visual discomfort from an increasing number of exhibitions that are being presented today. Was I alone in developing a migraine each time I passed the large illuminated wheel of colour in the first room in the National Gallery’s Making Colour exhibition? The start of this trend was I think the over-theatrical lighting used (again by the National Gallery, which has a dedicated team researching lighting) in the Sacred Made Real exhibition of Spanish religious sculpture four years ago. It may well be that the lighting succeeded in making people look more closely at what they would otherwise have ignored. But you don’t need any such enhancement to present Rembrandt – unvarnished, please.

From → Art history

  1. Very interesting, Neil. I went to Beningborough Hall recently to have a close look at the Kit Kat portraits by Kneller and was appalled to see that all of the blinds had been pulled down to the point that my aging eyes had great difficulty in seeing anything. Fortunately the curator suggested that I wait for the lowering sun to bounce off the floor which provided excellent ambient lighting.

  2. Stately houses often have the added problems of fabrics: probably the easiest way for the layman to observe the destructive power of photons. These balances are not easy to manage, particularly when public interest continues to increase

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  1. What’s wrong with art exhibitions? | Neil Jeffares
  2. Vigée Le Brun at the Grand Palais | Neil Jeffares

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