照明是每单位区域表面上的总发光通量。它以Lux（LX）为单位。
1 ph = 10,000 II
1 II = 0 ph
例子:
将15 光转换为照明指数：
15 ph = 150,000 II
| 光 | 照明指数 |
|---|---|
| 0.01 ph | 100 II |
| 0.1 ph | 1,000 II |
| 1 ph | 10,000 II |
| 2 ph | 20,000 II |
| 3 ph | 30,000 II |
| 5 ph | 50,000 II |
| 10 ph | 100,000 II |
| 20 ph | 200,000 II |
| 30 ph | 300,000 II |
| 40 ph | 400,000 II |
| 50 ph | 500,000 II |
| 60 ph | 600,000 II |
| 70 ph | 700,000 II |
| 80 ph | 800,000 II |
| 90 ph | 900,000 II |
| 100 ph | 1,000,000 II |
| 250 ph | 2,500,000 II |
| 500 ph | 5,000,000 II |
| 750 ph | 7,500,000 II |
| 1000 ph | 10,000,000 II |
| 10000 ph | 100,000,000 II |
| 100000 ph | 1,000,000,000 II |
规则