Talk:Lumen (unit)

message: The reason that higher-voltage incandescent lamps have fewer lumens per watts is very simple. This was alluded to in the earlier ″Light output and lifetime″ section of this article. The following is a more explicit description of the difference in lumens versus operating voltage.
The main failure mode is evaporation of the tungsten filament. Evaporation causes the filament to become thinner. The higher-voltage lamp is designed start with a thinner filament than that of a lower-voltage, or it would draw too much wattage, operate at a much higher temperature and have a very short life. Thinning alone is not enough to make a product acceptable because that would make the life too short and also make it fail too easily from a minor mechanical shock. Dmc7 (talk) 23:35, 18 August 2017 (UTC)
thread_title: One more clarification

message: As a reader of this page, I didn't find the thing I was looking for: a table 
relating incandescent bulb wattage to lumens.  —Preceding unsigned comment added by 192.132.94.130 (talk) 17:10, 11 January 2011 (UTC)
replies: text: You want Incandescent light bulb#Efficiency comparisons.--Srleffler (talk) 03:30, 12 January 2011 (UTC)
thread_title:  Example Table? 

message: I removed the mostly-redundant kitchen light example, for two reasons: first, the flux given seemed a bit high for an actual fixture. Four 4' T8 fluorescent tubes output about 10 klx. More importantly, putting the same fixture in a larger room does not uniformly reduce the illuminance. Assuming the same ceiling height, the illuminance right under the fixture might be almost the same but the illuminance near the walls of the larger room would be lower. One could think about average illuminance, but that would be pointless. You don't measure the average illuminance across a whole room, nor is that what is important for use. --Srleffler (talk) 17:26, 23 June 2011 (UTC)
thread_title:  Kitchen example 

message: This sentence (from the Explanation section) should be put in the introduction:
:The lumen can be thought of casually as a measure of the total "amount" of visible light in some defined beam or angle, or emitted from some source.
It immediately and clearly explaines what Lumen is. The introduction of this article is too complex as it is. While an in-depth explanation is needed, I think that the first paragraph should be easier to understand. - GeiwTeol 22:58, 15 July 2011 (UTC)
replies: text: Good idea. I reworked the intro based on your suggestion.--Srleffler (talk) 23:36, 15 July 2011 (UTC)

text: I reworked the paragraph with the equation.  Hope it's more clear now.  (not less clear!!) OsamaBinLogin (talk) 16:36, 25 May 2017 (UTC)
thread_title:  Clarification of the Introduction 

message: I came here looking for a section about the history/origin of the unit. --oKtosiTe talk 09:29, 27 September 2011 (UTC)
replies: text: You might be interested in Candela, which has a little bit of relevant history.--Srleffler (talk) 04:26, 28 September 2011 (UTC)
thread_title:  History? 

message: Can we work some of this in under Lighting?
 http://www.lvrj.com/sponsored/lumens-cfls-and-leds-a-light-bulb-guide-for-new-regulations.html?ref=498  
:. . . the following light bulbs all produce roughly the same amount of light (450 lumens): 40-watt incandescent, 29-watt halogen, 11-watt compact fluorescent (CFL) and 9-watt LED. It's still important to pay attention to wattage to make sure you don't exceed the recommended level for your lamp, but it's increasingly unlikely that you'll exceed that level as you purchase more efficient bulbs.
Thanks -- Jo3sampl (talk) 04:49, 8 November 2011 (UTC)
replies: text: The text I quoted above is labeled as "promotional". I'll look for similar info from a more reliable source (although there's no obvious reason to misstate what's essentially how-to-buy data). I think a lot of people get to this page looking for a rough quide to the new labelling standard -- we think we know what a 100w bulb will do, and we want to know if a 1600-lumen bulb is essentially comparable for our purposes. I didn't find conversion help at the Incandescent light article. -- Cheers/Jo3sampl (talk) 12:56, 8 November 2011 (UTC)
thread_title:  Lots of people looking for something like this? 

message: There's a nice table at http://www.energy.ca.gov/lightbulbs/lightbulb_faqs.html. -- Jo3sampl (talk) 13:19, 8 November 2011 (UTC)
thread_title:  Conversion chart for those who think in watts 

message: The source 3 "OSRAM DULUX energisparepærer" (pdf). Osram.dk. Retrieved May 25, 2013. is now a 404 error.
Napishtim (talk) 09:52, 22 July 2014 (UTC)
replies: text: Marked.--Srleffler (talk) 04:14, 23 July 2014 (UTC)
thread_title:  Expired source 

message: I have one LED lamp rated 420 lm at 8 W energy consumption and another one rated 806 lm and 9,5 W. So the second lamp seems to be much more efficient. But when you look a little closer, the second lamp only lights up 160 degrees while the first one has an emitting angle of 330 degrees (which seems also much closer to the characteristics of a standard incandescent light bulb). Wouldn't it be more appropriate to rate those lamps according to the total amount of energy they emit as visible light? BerlinSight (talk) 22:52, 30 September 2014 (UTC)
replies: text: That's essentially what rating them in lumens does. Lumens are a measure of the total "amount" of visible light emitted by the bulb per second. The advantage of using lumens rather than "energy emitted as visible light" is that lumens take into account the fact that the spectrum of the light affects how bright it appears.--Srleffler (talk) 04:40, 1 October 2014 (UTC)
thread_title:  Isn't it misleading to measure lamps for lighting in lumens? 

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thread_title:  External links modified 

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thread_title: Assessment comment

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thread_title:  External links modified 

message: There is no mention in the article of the ISO 21118 standard for a lumen - only the ANSI standard. There is confusion about the difference in methodology and in comparing the units. Gpurinton (talk) 07:52, 22 July 2021 (UTC)
thread_title: ISO standard