View Full Version : Practical considerations regarding currently available LED

T. Ashley McGrew
06-20-2012, 04:19 PM
This is a very hot topic pretty much everywhere these days. I wanted to share a post that I came across on the Museum and Art Gallery Lighting (http://www.linkedin.com/groups?gid=1860848&trk=myg_ugrp_ovr)group by Clint Paugh - Lighting Designer and interim Manager of Fabrication at The Nelson-Atkins Museum of Art.
I liked it because it discussed real - life practical issues. I also liked it because in my experience the many of folks who tout the use of LEDs unconditionally are not people who light artwork for a living. More frequently they are folks who design "spaces" or "create experiences" or whatever. Sometimes they are folks who mostly just sit and crunch numbers at a desk. Often those kinds of perspectives while certainly interesting are at odds with the mission that we have as museum professionals.
If not exactly for the nuts and bolts at least for the best current theory and a guide to purchasing LED products you should go to the Getty website and ask them to send you a copy of "Guidelines for Selecting Solid-State Lighting for Museums"
Many thanks to Clint for sharing his comments below



Lately I have been receiving a lot of inquires from other staff members about LED lights and if or when we plan to use them. As a result, I thought it a good idea to synopsize:
After a couple of years of being approached by innumerable salespersons and companies, both known and unknown, wanting to show me their LEDs, and promising that they had now solved all of the issues with LEDs and that I wasn’t even going to be able to tell the difference between their LEDs and the tungsten halogens lamps (bulbs) we currently use, I devised a plan.
First, I identified three places in the museum where it would be best to try LEDs before moving into the main galleries: Chinese stairwell track fixtures on the big Buddha, track lights on Benton’s in Atkins Auditorium, and track lights in Bloch Lobby. I chose these three places mainly because they are the most difficult art lights to access, but also because they are isolated areas where we could try a different type of lighting without people perceiving the difference between what is there and the other galleries. All three spaces also utilize different types of lamps – MR16s, PAR20s and PAR 38s – allowing me to attempt to find LED replacement for all three of these common lamps types.
Next, I sent to each and every one of those salespersons the exact type of fixtures and lamps we use in those three areas and invited them to provide me with their closest match. I initially contacted 11 LED lamp manufacturers to participate, but picked up two more along the way. Of those, 6 manufacturers got acceptable samples to me. I then made a spread sheet of all of the different lamps and all of the criteria I needed a lamp to meet in order to meet our high expectations for lighting at the Nelson. Those criteria were:

- fit in the fixtures we currently use
- a variety of lumen outputs to meet our needs
- a variety of beam spreads at least as good as the lamps we currently use
- color temperature in the 2700 to 3000 Kelvin range
- good color rendering
- consistent lamp to lamp color
- consistent lamp to lamp beam spread and beam quality
- optics that work with the lenses we currently use in our fixtures
- comparable throw distance to existing lamps we use

I then sat up a test area on the second floor where I could go through each of the samples one by one, look at them on their own, compare them to the tungsten-halogens we use and compare them side by side to one another. What I found was that, while there were certainly some LEDs that came close in many ways to matching the tungsten-halogens we use – and in some cases had better beam quality – there was still some room for improvement. I also found that there was not one single manufacturer that offered everything I was looking for – in other words, I could get all of the wattages, and beam spreads, etc. I need, but not from a single manufacturer. Considering the differences between the manufacturers, especially in color, mixing is not an option.
This lead me to believe that it is not yet time for us to start using LEDs at the Nelson-Atkins. That decision has, since then, been reinforced by two more developments.
One is that since I did the tests, most of those same manufacturers have approached me with a newer, better LED. This tells me that they know they still can and need to improve and, more importantly, that LEDs are still changing so quickly that any line of LED lamps we invest in now could be obsolete within a couple of years, leaving us to go through this whole process again.
The other new factor is that, more and more, the fixture manufacturers are diving into the LED market with LED fixtures to fit our track and/or LED retrofit kits to convert our existing track heads to LED. The intriguing part about this is that Edison-Price, who’s fixtures we use in the Bloch Building and many of the recently renovated galleries in the Nelson Building, designs with museums in mind and may be better suited to meeting our exacting standards. The early LED fixture sample I have seen from Edison Price is promising, but they have told me it is early and they are already working to improve it.
Ultimately, based on all of this, I decided to wait at least another year before looking at LEDs again - at which time, perhaps the LED market will have settled down, the consistency of LEDs will have improved, the range of wattages and beam spreads will have increased and the LED fixture possibilities will be more clear. While I continue to hear of more museum’s taking the leap into LEDs, there are still plenty like me, who feel that it just isn’t the right time yet.