In addition to wattage and light efficiency, what other factors affect the brightness of lamps and lanterns?

Wattage is one of the first things we look at when choosing a lamp (light source/bulb). So, when choosing lamps and lanterns, in addition to we see the wattage, photosynthetic efficiency, consider that affect brightness (what is the difference between the intensity of illumination and brightness) factors? In other words, what other factors should we consider before deciding what wattage to buy?  

  First of all, since we want to say brightness, then we have to mention a concept: luminous flux (LX), which is a standard value of illumination, the unit is lumens (LM/㎡)

  Light flux refers to the radiated power that the human eye can feel. In general, it is the amount of light that the human eye can see per unit area. Here is a formula: 1LX =1 LM /㎡, refers to, the object is uniformly illuminated by light, in 1 square meter area of the luminous flux is 1 lumen, its illuminance is 1 lux.

  Second, understand the concept of light flux, the second step, we should look at the area of the house or space

  According to the reference values in the figure above, if the area of a room is 10 square meters, 10㎡×(100~300) Lm /㎡=1000~ 3000Lm of light flux.

  Third, the function of the space often determines the height of its brightness

  Use the study that reads study, with the bedroom that uses to rest, be different obviously to the requirement with illuminance. For example, as mentioned in the above table, the general activity is 100LM/㎡, while the writing and reading need 300LM/㎡. But if the person is in the bedroom, also have reading and study demand at the same time, be about to use "mixed illumination" means to operate, add auxiliary lighting lamps and lanterns namely, be like desk lamp, floor lamp, wall lamp belong to.

  Its four, when buying a lamp, take a look at light effect value

  The light efficiency value reflects the relationship between wattage and light flux, that is, how many lumens (Lm) light can be produced by the power of the lamp per watt, that is, light flux = wattage * light efficiency. Take a 20W bulb for example. Assuming that the light efficiency is 100lm/W, then the luminous flux that can be produced after the bulb is electrified is 20W*100lm/W=2000lm.

  What need to carry is, as a result of the reason such as craft, technology, the luminous effect of bulb of every brand, manufacturer, model is different, we can see package box or instruction manual when choosing, perhaps seek advice to the businessman directly.

  Fifth, no main lamp design can appear brightness is not enough

  In general, we think that the luminous flux is the sum of several lamps, that is, other things being equal, the more lamps, the higher the luminous flux. Accordingly, will tell from this Angle, room brightness is enough enough, have advocate lamp to do not concern with.

  For example, a living room of 20㎡, the owner required to reach 2000LM of light flux. The luminous flux of a particular lamp is 200LM/W. So, in theory, 10 of the same lamps should do the trick. Of course, when we are really doing lighting design, we tend to be affected by many other factors. For example, the room has tall furniture, or the furniture, walls, floors of the overall tone is too dark, or too light, will affect the final brightness and perception of the human eye.