Coming in 2011: New Labels for Light Bulb Packaging
Under direction from Congress to re-examine the current labels, the FTC is announcing a final rule that will require the new labels on light bulb packages. For the first time, the label on the front of the package will emphasize the bulbs’ brightness as measured in lumens, rather than a measurement of watts. The new front-of-package labels also will include the estimated yearly energy cost for the particular type of bulb.
This will allow one to make an easier comparison of bulb’s brightness, but it should be noted that lumen is the unit of luminous flux, which is the brightness as perceived by the human eye. The eye’s efficiency peaks at about 550 nm, and tapers off at the red and blue ends of the spectrum, and the lumen compensates for this. In other words, it’s not the actual amount of visible light energy given off, it’s how bright it looks. This is a trick used in the past by laser pointer manufacturers, when they started coming out with shorter-wavelength (i.e. redder or non-red) devices. Because the eye was more sensitive, they appeared brighter, even though the power was actually smaller. 1 mW of green can be as bright as ~5 mW of red, depending on the exact wavelengths involved.
huh? what’s the difference between “amount of visible light energy” and “how bright it looks?”
I thought the word “visible” already included that weighting function of the eye…
why is there that 1/683 factor in the lumen? couldn’t it just be weighted watts? Then it would be obvious that a 100W lightbulb produces only 3W of “light” and 97W heat.
anyway, dim down the lights in the lab and its very easy to see 785nm lasers, 808nm lasers and also 830nm lasers. I’ve never seen a dim red spot from anything longer than this. How about anyone else?
(staring right into a 1064nm beam is not advisable… I don’t think it would be visible anyway)
Watts is a unit of power, but not all sources appear to be the same brightness. The 1/683 is a weighting factor; there are 683 lumens/Watt at the peak sensitivity, meaning you would need more power to appear as bright at other wavelengths.
So even saying there are 3W of visible isn’t enough information, because 3W of green appears to be much brighter than 3W of blue or red.
The danger here is that your “dim” 830 nm laser is probably relatively powerful, and poses a danger because you will not have the blink reflex when you see it, because it appears to be dim.
now if they could just switch to the metric system.
There is a simple diagnostic. Items bearing this EPA-granted logo are, on the UL-observed average, LESS energy efficient than what they replace. Always look for the warning logo,
http://www.film.org/film/greenerSETS/images/Energy-Star_1.gif
I’m disappointed that CRI isn’t included. Seems nobody has any regard for the quality of the light in the room…just brightness and temperature.