Description
Return duty-cycle mean illuminance and accumulated exposure.
Illuminance, accumulated light exposure, polarization and color-coordinate differences are different optical quantities. Lux-hours combine illuminance and duration; one coordinate difference does not describe a complete color difference or an object’s susceptibility to damage. Optical and preservation interpretation require suitable calibration and material context.
Return duty-cycle mean illuminance and accumulated exposure.
When to use this tool
Use Display Light Pulse Duty Factor when checking the stated illumination, exposure or optical-coordinate term.
How to use the tool and how it works
- Enter onIlluminance, offIlluminance, onSeconds, periodSeconds, exposureHours. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read meanIlluminance, exposure. Use the output convention below.
Return duty-cycle mean illuminance and accumulated exposure. Require nonnegative on/off illuminance, period > 0, onSeconds within period and exposureHours >= 0; time-weight both levels, exposure = mean*hours.1
Light exposure accumulates across illumination and time, while material sensitivity affects preservation risk. This lux-hour calculation does not select a suitable display limit or predict damage.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| onIlluminance | Illuminance in lux while on. | Required. Finite number; minimum 0. |
| offIlluminance | Illuminance in lux during the rest of the cycle; included in exposure. | Required. Finite number; minimum 0. |
| onSeconds | On Seconds | Required. Finite number; minimum 0. |
| periodSeconds | Period Seconds | Required. Finite number; strictly above 0. |
| exposureHours | Exposure Hours | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| meanIlluminance | Mean Illuminance | Required. Finite number. |
| exposure | Mean illuminance*exposureHours, in lux-hours. | Required. Finite number. |
{
"input": {
"onIlluminance": 100,
"offIlluminance": 0,
"onSeconds": 1,
"periodSeconds": 4,
"exposureHours": 8
},
"output": {
"meanIlluminance": 25,
"exposure": 200
}
}Limitations and assumptions
- Illuminance in lux gives lux-hours; this assumes repeated stable duty cycles and does not determine a safe light dose or actual damage.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use calibrated lighting/color measurements and an object-specific conservation assessment for display limits, color fidelity or deterioration risk.
References
-
Calculation and input contract: art-conservation/display-light-pulse-duty-factor — tool.io
-
Agent of Deterioration: Light, Ultraviolet and Infrared — Stefan Michalski, Canadian Conservation Institute
Similar or alternative tools
- Conservation Light Dose Dark Time Adjustment
Return lit hours and nominal illuminance exposure.
- Artwork Photography Polarizer Angle Factor
Return a Malus-law polarizer factor with supplied leakage.