You won’t necessarily be using these units in any practical way with projection mapping, but you may notice them on the Projector Central calculator, so it’s worth noting that while their brightness calculator can be helpful, it’s primarily focused on helping you meet the Society of Motion Picture and Television Engineers’ recommendations for cinema screens. The imperial unit of luminance, the foot-lambert (fL), measures candela/ft 2 and the SI unit is simply candel a/m 2 although it is more and more frequently referred to as a nit. In photometry, luminance refers to both reflected light and light emitted directly from a source, like the screen you’re using to read this. The materials in the scene you’re projection mapping will all have different levels of luminance or emittance, which tells us how bright or intense they appear to our eyes. If your projected area was only half that size, each of those lumen ratings would produce twice as many lux, and if your projected area was only a quarter of that size, each lumen rating would produce four times as many lux of illumination, and so on.Īny one of those projectors pointed at a white wall will appear much brighter than if pointed at a black wall, as the amount of light reflecting to your eye changes based on the reflecting surface’s properties. 1000 lumens will produce an average of 35.2 lux at that size, 5000 lumens will produce an average of 175.8 lux, and 10,000 lumens will produce an average of 351.6 lux of illumination. Once we know the area of the projection, we can easily calculate the average lux that any given lumen rating will produce within that area by dividing our total light output in lumens by the projected area those lumens will illuminate. When we multiply 4m x 7.11m we have a total projected area of 28.44 square meters. With projection mapping, you don’t need to be set up perpendicular to your subject, in which case your frame might be more of a trapezoid than a rectangle, but for the sake of simplicity let’s assume that we are projecting head-on. That means the horizontal width of your projection will be 7.11 meters. Light appearance, measured by correlated color temperature (CCT) on the Kelvin (K) scale, from warm to cool.Say you wanted to project on a 4-meter tall mural and your projector has an aspect ratio of 16:9.Estimated yearly energy cost (similar to the EnergyGuide label).The label includes the following information:

Like the helpful nutrition label on food products, the Lighting Facts label helps consumers understand what they are really purchasing. It helps people buy the lightbulbs that are right for them. To help consumers, the Federal Trade Commission requires manufacturers to include a product label for light bulbs on the package. What Should You Look For on the Package? The Lighting Facts Label Replace a 40W bulb with an energy-saving bulb that gives you about 450 lumens.Replace a 60W bulb with an energy-saving bulb that gives you about 800 lumens.Replace a 75W bulb with an energy-saving bulb that gives you about 1100 lumens.If you want something dimmer, go for fewer lumens if you prefer brighter light, look for more lumens. To replace a 100 watt (W) incandescent bulb, look for a bulb that gives you about 1600 lumens.The brightness, or lumen levels, of the lights in your home may vary widely, so here's a rule of thumb: So when buying light bulbs, think lumens, not watts. Lumens let you buy the amount of light you want. More lumens means it's a brighter light fewer lumens means it's a dimmer light. Lumens measure how much light you are getting from a bulb. A lumen is a measure of the amount of brightness of a lightbulb - the higher the number of lumens, the brighter the lightbulb. When you're shopping for light bulbs, think about the brightness you want by comparing lumens instead of watts. But now it makes more sense to buy lights based on how much light they provide. In the past, we bought light bulbs based on how much energy, or watts, they use.

This label makes it easy to compare bulb brightness, color, life, and estimated operating cost for the year. When you're shopping for light bulbs, compare lumens to be sure you're getting the amount of light, or level of brightness, you want.

Lumens brightness