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Museums lighting and technological change

The museum and gallery is far from immune from pressures to reduce energy usage both to reduce operating costs and operate in a more environmentally friendly way. Lighting is often perceived as a major energy user, as a result is often targeted to achieve savings. We also find that our favorite museums lighting tool of the past two decades, the low voltage reflector lamp, is falling foul of the latest European legislation that was intended primarily to reduce lighting energy use in the domestic sector where reflector lamps in cheap downlights have become the default solution in new housing developments. These factors are forcing museums to reconsider their approach to lighting with a degree of haste that has great potential for erroneous and misinformed decisions.

The legislation is part two of the domestic lighting Ecodesign regulations, part one dealt the deathblow to the incandescent lamp. This new regulation effectively removes from the general market MR16 and AR111 lamps that do not use either infra red coating or Xenon gas fill from September 2013 The exact impact is impossible to determine as the lamp manufacturers remain stubbornly silent as to what lamps they will and will not make available in these efficient versions. My expectation is that most lamps not already available with these technologies will no longer exist. In museum terms the greatest problems will be the loss of the ENL MR16 lamp which is specifically designed for fibre optic lighting used in vitrines and the very narrow AR111 lamps that cannot be made with IR technology but is a vital tool to isloate specific objects from typical high ceiling levels.

There remains a stubbornly persistent expectation that LED replacement lamps can simply be substituted for reflector lamps. Sadly this is a very dangerous error. Most of these replacement lamps cannot be dimmed, have poor colour rendition, limited ranges of beam angles and certainly none are very narrow. They are also mostly intended to fit in open fittings to allow cooling, here many museum fittings have closed backs to prevent light scatter. Many museum fittings use dimmable or self dimming transformers which either do not operate these LED products or cause flicker and strobing. The lower wattage of the LED is usually below the lower limit of transformers designed for Low Voltage halogen lamps that are between 20W and 50W. The result is potential failure of the LED lamp or the fitting.

What seems to be a simple solution will result in significant wasted money, poor quality exhibition lighting and potential excess light exposure where dimmed lamps of specific beam angle are replaced with lamps of the incorrect beam angle operating at full intensity as the dimming no longer works. We are already seeing this happening across many exhibitions and in one instance have seen an exhibition revert to Low Voltage Tungsten Halogen after a year as the expensive LED replacement lamps had failed.

There is no doubt that LED technology has now developed to a point where suitable products exist for museum applications. The problem is that this requires specific fittings with the appropriate LED devices. We also find that efficiency gains are much less than is generally accepted, we even know of one fitting that is intended specifically for musuem use that is half as efficient than an equivalent Low Voltage Tungsten Halogen fitting when focussed to its narrowest distribution. Certainly quality LEDs offer the ability to be dimmed without the yellowing that occurs as you dim Tungsten Halogen lamps and they also offer a clarity on some objects from the increased levels of blue in the spectrum, these can be useful in displaying water colours in particular where the low light levels required for conservation have often resulted in apparent gloom.

LED may be an appropriate choice for museum lighting however the range of products and the variation in performance are so huge that it is unreasonable to expect anyone other than an experienced, specialist, museum lighting designer to guarantee a good and successful result providing both lighting quality and energy reduction.

Over the past 30 years of my involvement with museum lighting we have made significant improvements in lighting quality, maintainability and protection for displayed works. I am really concerned that many of these improvements will be lost in the next few years if lighting decisions are delegated to electricians and technicians instructed to save energy as a primary goal. As has been said many times, lighting is most vitally important in museums where the visitor’s access to the majority of objects is usually by sight alone. Degrading the visual environment with poor “energy saving” lighting has to be a grave error.

Museums really need to develop a strategic approach that will ensure the transition from older lighting technology to more efficient lighting can be managed effectively. Funding considerations will almost certainly require that a staged approach is developed over a number of years and contingency solutions including forward stockholding of specific lamps types needs to be planned before the legislation deadline of September 2013.