How to test the projector’s lumens?

How to test the projector’s lumens?

  •  We test the Brightness Parameters of the Projector according to ANSI Standards.
  •  First we will introduce the word "ANSI". ANSI is short words of "American National   Standards Institute", founded in 1918.
  •  American National Standards Institute's standards, the vast majority from the   professional standards. On the other hand, professional associations, associations can   also be based on existing national standards to develop certain product standards. ANSI  standards are voluntary.
  • We will give you the two different result: American and Chinese Standards. They have the same test way. The difference is that the Chinese standard result are more than four times that of American.

Step 1:

Adjust the brightness and contrast of the projector. Let the projector can distinguish eight different shades of gray color. Under the situation meet the ANSI standards requirements. Because blindly high brightness and contrast will make the image distortion.

Step 2:

Show the White picture on the wall. Record the projection screen size. We will use the screen size to calculate the lumens later.

Step 3:

Due to the characteristic of the projector, the middle part of the screen's brightness is greater than the surrounding parting. So we use the Illuminometer to record the different point on the screen. Then we will get the White Picture average Lux result for whole screen.

Step 4:

Then copy the same method to get the whole Black Picture Average Lux result. Because we need reduce the Lux Produced by the environment.

Illumination is a unit of light intensity, its physical meaning is to illuminate the luminous flux per unit area, illumination unit is the number of lumens per square meter (Lumen), So we get lux (Lux) formula: 1Lux = 1Lumen / m2.

First,after we adjust the image to ANSI standards.And get the screen size from step 2: Height=1.14m, Width=2.0m. And get the white picture's average lux Ew=1401 lux, Black picture's average lux Eb=230 lux. So the lumens result is Φ = (1401 lux - 230 lux) x 1.14m x 2.0m = 2669.9 (lumens). And the Chinese lumens is ten times more than ANSI result, so the Chinese lumens is 2669.9 x 4 = 10679.6 lumens.

Picture 1 2 3 4 5 6 7 8 9 Average
White 1325 1477 1436 1354 1692 1626 1043 1309 1347 1401
Black 232 242 221 / / / 213 243 231 230
Picture White Black
1 1325 232
2 1477 242
3 1436 221
4 1354 /
5 1692 /
6 1626 /
7 1043 213
8 1309 243
9 1347 231
Average 1401 230

Calculate Error

Because of the error of ± 3% of the illuminance of the measuring instrument itself, and the influence of using different ambient light, the final test results also have some errors.

If you think the one screen size is not accurate, you can change the projection distance to screen to have a different screen size. And copy the same steps to get the lumens with different screen size. At the end calculate the average lumens is done.

Sometimes the seller gives you the Lamp or Bulb's factory inspection ANSI lumens. But it is not the real lumens projection to screen. Because the light source inside the machine exist package lax, power instability, optical lens attenuation and other issues, it cannot be 100% projection to the screen. So we need to test out the true lumens to the screen.

After continuous working 2 hours. The projector's temperature will be higher. And the fan will work harder than beginning. It will make a louder noise. So we give the noise and temperature result after 2 hours continuous working. For NIERBO CH4000 projector, it is built in Osram LED lamp, so the noise and temperature will not be big difference than beginning. The noise is 48.0 dB, the temperature is 34.0 ℃.

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