Specimen uses art and science to challenge your eyesight—and it’s set to a funky groove.
Source: Meet Specimen, an iOS game that proves you can’t see color as well as you thought | Macworld
Specimen uses art and science to challenge your eyesight—and it’s set to a funky groove.
Source: Meet Specimen, an iOS game that proves you can’t see color as well as you thought | Macworld
The connection between our emotions and how we see the world is more than just metaphor, one study found.
Source: The scientific reason your world brightens up when you do
Scientists say warming waters and melting ice were to blame for levels rising faster than 50 years ago and ‘it’s very likely to get worse’
Source: Global sea levels have risen 8cm since 1992, Nasa research shows
You may be familiar with the idea of a color gamut from displays or from RGB LED fixtures. In both cases the gamut describes the full range of colors that the device can create. In TM-30-15 IES Method for Evaluating Light Source Color Rendition gamut (Rg) has a somewhat different meaning. It refers to the average color shift of the 99 color evaluation samples (CES) under the test light source when compared to the reference light source. The reference source used in Rg is the same source used when calculating color fidelity (Rf) (as opposed to a fixed reference source as has been proposed in other gamut metrics).
A gamut index of 100 means that, on average, the test light source doesn’t change the hue or saturation of the CES compared to the reference source. An Rg above 100 indicates that the test light source, on average, increases the saturation of the CES producing colors that are more vivid. An Rg below 100 indicates that the test light source decreases the saturation of the CES producing colors that are less saturated.
The addition of a gamut index is a huge improvement over the single CRI (Ra) number that we’re used to. With Ra, every shift from a match to the reference source, whether it increases or decreases saturation, is treated equally and the direction of the shift is not reported. However, this is important information. For instance, research has shown that in many situations most people prefer a slight increase in color saturation. With Rg designers know the direction of the color shift, and the TM-30 calculation tool also shows the shift by hue and for each of the CES.
What’s the relationship between Rf and Rg? If Rf is 100 (a match to the reference source) Rg must also be 100. If the Rf calculation doesn’t indicate a mismatch with the reference source then there is no change in saturation. As the Rf value falls the potential range of Rg above and below 100 (indicating an increase or a decrease in saturation) grows. The calculation tool includes a chart that shows this relationship and gives a visual indication of where the light source in question fits.
Another graphic, the Color Distortion Icon, is plotted on the CAM02-UCS color space. In this graphic both the reference source and the test source are shown, along with an indication of the direction and magnitude of the hue shift caused by the test source. Finally, we can even look at the color shift for each of the 99 CES.
A designer using TM-30 now has three big picture metrics to evaluate a light source: color fidelity (Rf), color gamut (Rg), and correleated color temperature (CCT). The designer can use TM-30’s calculation tool to examine the Rf and Rg of a light souce in as much detail as the project merits, from a very broad overview to a very detailed, color by color, evaluation.
The one thing that TM-30 does not do is provide guidance on the significance of the values it calculates. It is a Technical Memorandum that describes two calculation proceedures, not a design guide for using the results of those proceedures. Guidance will come later in the form of a TM-30 addenda or a design guide prepared by the IES, or guides prepared by other parties. In the meantime designers can begin to build their own understanding by comparing Rf and Rg values to the their visual evaluation of the light source, and by sharing the results of their work with others.
The pubication date has not been set, but now that the TM has been approved by the IES board of directors it should be available soon. Keep an eye on the IES bookstore and on trade publications for updates. In my opinion TM-30 is a huge improvement over CRI, and I hope that the industry enthusiastically adopts it.
Note: This post was originally published on June 15, 2015 but was taken down when the IES contacted me and claimed copyright to all graphics produced by the TM-30 calculation tool. This seems to me as absurd as Adobe claiming copyright to all pictures edited in Photoshop, but I didn’t have the time to argue. I took down the original post and have reposted it here, without graphics, and edited the text to omit references to graphics.
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.