are lumens a linear scale?
233089
Lumens do add up. So if you have one n lumen flashlight and another m lumen flashlight the total luminous flux will be n+m. However interestingly our eyes (and ears) don't operate on a linear scale. 2x the lumens will not be perceived as 2 times the brightness because our eyes and ears work on a logarithmic scale.
1042052
LM-80 refers to a method for measuring the lumen depreciation of solid-state light sources, such as LED packages, modules and arrays. Typically, LED component manufacturers each report lumen maintenance data using their own methodology making it vary hard to compare “like for like”.
391048
The intensity (or illuminance or irradiance) of light or other linear waves radiating from a point source (energy per unit of area perpendicular to the source) is inversely proportional to the square of the distance from the source; so an object (of the same size) twice as far away, receives only one-quarter the energy ...
1065726
The difference between the units lumen and lux is that the lux takes into account the area over which the luminous flux is spread. A flux of 1000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance of 1000 lux. ... Mathematically, 1 lx = 1 lm/m2.
820116
Light color or appearance is measured on the Kelvin (K) temperature scale, and it's the difference in soft white versus daylight bulbs. Lower Kelvin numbers mean more yellow light; the higher the Kelvin number, the whiter or bluer the light.
1089687
Current theory holds that the: » Minimum amount of lighting needed to sustain growth is around 2000 lumens per square foot. » Mid range is around 5000 lumens per square foot. » Optimal is 7000, or higher, lumens per square foot.
344886
The lumen is the standard unit of luminous flux. Luminous flux is the measure of perceived power of light by the human eye. We measure luminous flux in lumens, just as we might measure speed in miles per hour. ... Well, luminous flux is measurable, unlike brightness which is a perception.
851081
Flashlights, for example, are usually measured in lumens. Candlepower and lumens measure different light qualities, and 1 candlepower equals 12.57 lumens. When measuring lumens, you can also think of it as the light illuminated in a 1-square-foot area one foot away from a single candle.
1030223
When I say apparent brightness, I mean how bright the star appears to a detector here on Earth. The luminosity of a star, on the other hand, is the amount of light it emits from its surface. The difference between luminosity and apparent brightness depends on distance.
594402
Lumens equal brightness; watts do not. (Watts measure energy used.) CFLs and LEDs use much fewer watts than incandescents with the same brightness. As a rule, you'll replace a standard 75-watt bulb with an energy-saving bulb of about 1100 lumens.
674879
In simple terms, a light's lumen value describes the brightness and the Kelvin temperature describes its color.
1115447
A simplistic explanation is that lumens equate to a flashlight's brightness, and while that's not entirely true, it's a good rule of thumb: the bigger the number of lumens, the brighter the flashlight will appear to be. (For more info, see our piece on Measuring light output: Lumens vs Out The Front lumens.)
447946
That means that you should go for a projector with thousands of lumens, not hundreds. For dark rooms, 1,000 lumens usually works fine. ... For daylight viewing outdoors, go for the highest possible lumens. If the screen is quite large, say 40 feet, you'll want to consider a 5,500-lumen projector.
34928
Kitchen: 3,000 to 4,000 lumens. Dining room: 3,000 to 4,000 lumens. Living room: 1,000 to 2,000 lumens.
652096
Lumens and Watts Standard 100-watt bulbs produce about 1600 lumens. Watts: The amount of energy a light bulb uses. The lower the watts, the lower the electric bill. CFLs and LEDs have a lower wattage than incandescent bulbs but emit the same light output.
263657
The E-Series has 10 dimming zones on the 43-, 50- and 55-inch sizes, 12 on the 65- and 70-inch sizes, and 16 on the 75-incher. The M-Series ranges from 32 to 48 zones depending on size, which helps explain its superior image quality. Just a few zones are better than none, however.
940383
Als Antwort auf Leonardo David: Mean Lumens is the lumen output that Lighting Designers use when planning foot candles in a space. The difference in Initial Lumens, Mean Lumens and lumen output at the end of life of the light source is a measurement of Lumen Maintenance/ Depreciation.