| Recommended total exposed limits in museum (IESNA) | ||
| Objects | Illuminance | Lux-hours per year |
| Highly susceptible―silk, textiles, watercolors, furs, lace, etc. | 50 | 50,000 |
| Moderately susceptible―oil painting, leather, wood, etc. | 200 | 480,000 |
| Least susceptible―metal, glass, ceramic, stone, jewelry, etc. | Depends on exhibition situation | |