LED Use in the Museum Environment
You are probably aware of certain claims being made about the use of LED lighting technology in the museum environment. This paper will try to address those claims in a manner consistent with current, high quality, white light LED sources.
Claims have run the gamut from: LEDs have no UV, and no IR, and therefore any LED is the best source for lighting in museum environments, and lighting sensitive artwork, at any light levels…. to: LEDs are the most dangerous source that can be introduced, because the CRI is lousy, the spectrum has significant spikes, and they will permanently damage your artwork in no time.
As with most statements, the actual facts are somewhere in between, and require an understanding of where those statements are coming from.
Let’s start with a qualification of museum lighting. The current “standard” for most museum and gallery lighting is to use a Tungsten Halogen source, of the appropriate output for the desired light levels. Therefore, I will focus my comparison of sources between a high quality, high CRI halogen source, and a high quality, high CRI white light LED.
Halogen sources are the most commonly used source in museum lighting environments for several reasons. Those reasons are:
Spectral Distribution: Halogen light is full spectrum light. This means that if you analyze a spectral distribution chart (SPD), all colors from the violet end of the spectrum to the red end of the spectrum are present. Artwork that is illuminated by a full spectrum source will be rendered well. In addition, the energy output of the halogen spectrum is well documented, and well understood in terms of exposure to artwork. As a general statement, the most significant alteration of the halogen spectrum for museum lighting has been to filter out the ultra-violet component, and sometimes (although rarely in practice) filter out the IR component. In theory, you then have a source with full spectrum, visible light, insignificant amounts of UV, and insignificant amounts of IR. An SPD of this type of source would look like this: