Conservation Light Dose Dark Time Adjustment Tool

Description

Return lit hours and nominal illuminance 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 lit hours and nominal illuminance exposure.

When to use this tool

Use Conservation Light Dose Dark Time Adjustment when checking the stated illumination, exposure or optical-coordinate term.

How to use the tool and how it works

Enter illuminance, scheduledHours, darkHours, exposureDays. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read litHours, dose. Use the output convention below.

Return lit hours and nominal illuminance exposure. Require illuminance/darkHours >= 0, scheduledHours >= darkHours and nonnegative whole exposureDays; litHours = (scheduled-dark)*days, dose = illuminance*litHours.^[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
illuminance	Illuminance	Required. Finite number; minimum 0.
scheduledHours	Scheduled Hours	Required. Finite number.
darkHours	Dark hours per scheduled day, rather than over the entire run.	Required. Finite number; minimum 0.
exposureDays	Exposure Days	Required. Safe integer; minimum 0.

Output field	Interpretation	Returned shape
litHours	Lit Hours	Required. Finite number.
dose	Illuminance*litHours over all exposureDays, in lux-hours.	Required. Finite number.

json

{
  "input": {
    "illuminance": 50,
    "scheduledHours": 8,
    "darkHours": 2,
    "exposureDays": 100
  },
  "output": {
    "litHours": 600,
    "dose": 30000
  }
}

Limitations and assumptions

Scheduled/dark hours are per exposure day; lux gives lux-hours, without selecting safe conservation limits or predicting 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/conservation-light-dose-dark-time-adjustment — tool.io
Agent of Deterioration: Light, Ultraviolet and Infrared — Stefan Michalski, Canadian Conservation Institute

Similar or alternative tools

Display Light Pulse Duty Factor
Return duty-cycle mean illuminance and accumulated exposure.
Artwork Photography Polarizer Angle Factor
Return a Malus-law polarizer factor with supplied leakage.