The companion blog to the books Designing With Light and Fundamentals of Energy Efficient Lighting and Controls
Tomorrow is my first day of class at Pratt, so here we go again. I know that this shouldn’t become a thing, and I’m really trying but I can’t help myself! Here’s another video of a song related to light and featuring frightening hairstyles. This time it’s Styx singing Lights in 1980. (And no, I can’t explain Tommy Shaw’s sailor costume so don’t ask.)
For decades we have discussed solar as an energy of the future . But it’s already changing the game.
Source: Solar Energy: The Future Is Here – Plugged In – Scientific American Blog Network
Now that the IES has approved TM-30-15 IES Method for Evaluating Light Source Color Rendition they have begun their outreach and education on this significant metric. To that end, they have joined the DOE in presenting a webinar on September 15. The webinar will be hosted by Michael Royer of PNNL and Kevin Houser of Penn State University, two of the leaders of the committee that developed TM-30. Click here to register.
I was recently interviewed by Architectural SSL about Designing With Light and my work as a teacher and designer. Click here to read the interview.
ASHRAE has announced a 30-day public review and comment period for addendum to ASHRAE/USGBC/IES Standard 189.1-2014, beginning on July 24th. The addendum that concerns lighting designers corrects and clarifies a potentially confusing requirement in which a designer may conclude that bonus lighting power control factors from Table 9.6.3 Control Factors Used in Calculating Additional Interior LPD of ANSI/ASHRAE/IES Standard 90.1 cannot be used.
More information and instructions on commenting are at https://www.ashrae.org/standards-research–technology/public-review-drafts.
This month’s issue of Lighting Design + Application (LD+A) has a review of Designing With Light by Fred Oberkircher. He calls the book “beautifully imaged” and “one of the best lighting design texts.” Read the full review.
The 69th Annual Tony Awards are on CBS tonight at 8 pm. I was at the rehearsal this morning (see below) and I can tell you that it’s going to be a good show. Kristin Chenoweth and Alan Cumming are great fun. Check out this year’s nominees for best play and best musical (you can even stream it!), then get yourself some theatre tickets.
On May 29th the DOE issued a final clarification of energy conservation standards and test procedures for fluorescent lamp ballasts. The new rule reorganizes, reformats, and clarifies the scope of the energy conservation standards for fluorescent lamp ballasts. It includes establishing new active mode test procedures, standby and off mode test procedures, and revised active mode test procedures for fluorescent ballasts.
At last week’s Lightfair one of the presentations was Quantifying Color Rendition: A Path Forward. The presentation was the first public look at the (not yet approved) IES Method of quantifying color rendering. What is this new (not yet approved) IES Method? Let’s start with a quick review of the current color rendering metric, Color Rendering Index (officially CIE 013.3-1995 Method of Measuring and Specifying Color Rendering Properties of Light Source) or CRI.
CRI is a fidelity metric. It compares the color rendering properties of a light source to the properties of a light source of the same color temperature, either a black body radiator for color temperatures below 5000 K, or a model of daylight for color temperatures of 5000 K and above. First issued in 1965 and last updated in 1995, CRI has several known defects. It is based on outdated color science, there are too few color samples (only eight for the general color rendering index, or Ra), and the color samples are Munsell colors, not those of real world objects.
Finally, since the colors used don’t give equal weight to all wavelengths of visible light, as shown below, lamp manufacturers can optimize their lamps spectral power distribution (SPD) to achieve higher scores.
The new calculation procedure is called TM-30 IES Method for Evaluating Light Source Color Rendition. It is, in my opinion, substantially better than CRI for several reasons. A disclosure – the Color Metrics Task Group that developed TM-30 is an offshoot of the IES Color Committee, of which I am the vice-chair.
TM-30 is a dual metric system. It provides us with a measurement of fidelity (Rf), although using a completely different method than CRI. It also provides us with a measurement of gamut (Rg). In this case, gamut means that it gives us a number that tells us if a light source that scores lower than 100 on the fidelity metric (and is therefore not a match to the reference light source) increases saturation of colors making them more vibrant, or desaturates colors making them grey or dull. This gives us a much better understanding of the color rendering performance of the light source in question. These two numbers are supplemented with a variety of graphics. These include a graphic showing the color distortion produced by the lamp, a graphic showing the change in gamut, and a graph of the Rf and Rg indexes.
It’s the color samples and calculation procedure, however, that drive this new method. Among the improvements are:
TM-30 is in the final stages of balloting. I believe that it will be approved by the end of the summer. Once it is, I’ll have more to say and graphics to explain it better. Stay tuned.