Here's a riddle for you: How bright is a <a href="http://www.atgstores.com/50w-65w-incandescent-bulbs_36.html?&option0=optionA=267592|12185~Valu" target="_blank">60-watt light bulb</a>?
The answer, of course, is always going to be, "Uh ... about this bright? You know. Kinda bright, but not <em>too</em> bright." (Punctuates guesstimation with vague hand gestures.)
Like many riddles, it's impossible to answer because watts do not translate directly to light intensity. Wattage measures the electricity used to illuminate the bulb and two light bulbs with the same wattage can have different levels of brightness. Scientists and people in the lighting industry have units of measure that can help answer the riddle more precisely, although not too many people are familiar with the terminology.
The most common unit of light measurement (brightness) is the <em>lumen</em>, and you may even notice this word on <a href="http://www.atgstores.com/light-bulbs_7.html?linkloc=topnav" target="_blank">bulb</a> packaging. The tricky thing is that to understand lumens you must first know about <em>footcandles </em>and <em>candelas</em>, and no one ever puts that stuff on the packaging. In a lot of ways it's like starting a story with, "The butler did it."
So, in an effort to put all the pieces together: A footcandle is equal to one lumen per square foot, which is also equal to the illumination cast on a surface by a "one-candela" source one foot away.
Aha! So, what's a <em>candela</em>? It's roughly the amount of light given off by a common candle as expressed in a precise mathematical equation, as opposed to a wobbly flame. Add that into the mix and sprinkle some math into it to account for distance and angle, and what you get is this: 1 candela = 12.57 lumens. A little more math (ouch!) and we can estimate that a typical 60-watt incandescent light bulb puts out around 800-840 lumens. Some simple division and a bit of fudging and we can make the argument that the aforementioned bulb is as bright as 70 candles, give or take a few birthdays.
So, what's all this mean? You may think very little given the simple understanding that <em>more lumens</em> equals <em>more light</em>, but the benefit is that it provides a baseline across bulb types when other less reliable factors (watts!) start to fluctuate. In other words, knowing lumens can help you decide what kind of light is going to work best for you when choosing between <a href="http://www.atgstores.com/halogen-bulbs_38.html?linkLoc=topnav" target="_blank">halogen</a>, <a href="http://www.atgstores.com/incandescent-bulbs_36.html?linkLoc=topnav" target="_blank">incandescent</a>, <a href="http://www.atgstores.com/led-light-bulbs_1527.html?linkLoc=topnav" target="_blank">LED</a>, <a href="http://www.atgstores.com/fluorescent-light-bulbs_37.html?linkLoc=topnav" target="_blank">fluorescent</a> and other types of bulbs.
As a measure of comparison, if your new CFL or LED bulb produces around 800 lumens then you know it's giving you about the same amount of light that's provided by a 60-watt incandescent bulb, although with far less wattage.
<a href="http://www.atgstores.com/" target="_blank">ATGStores.com</a> is no dim bulb when it comes to lighting and lighting accessories, and if you're thinking of really lighting up the joint feel free to stop in and see what we have to offer.