Description
Compare supplied measured and reference image-channel values.
Conservation records distinguish measured areas, source-qualified condition labels, storage clearances and light exposure. Lux-hours measure photometric exposure, whereas material response depends on spectrum and sensitivity. A nominal inverse-square distance ratio or geometric mask share does not establish an appropriate treatment or safe display limit.
Compare supplied measured and reference image-channel values.
When to use this tool
Use Conservation Photo Color Patch Residual when you already have referenceChannelValue, measuredChannelValue and need to compare supplied measured and reference image-channel values.
How to use the tool and how it works
- Enter referenceChannelValue, measuredChannelValue. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read signedGap. Use the output convention below.
Return measuredChannelValue-referenceChannelValue with signs preserved.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| referenceChannelValue | Reference Channel Value | Required. Finite number. |
| measuredChannelValue | Measured Channel Value | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| signedGap | Signed Gap | Required. Finite number. |
{
"input": {
"referenceChannelValue": 12,
"measuredChannelValue": 17
},
"output": {
"signedGap": 5
}
}Limitations and assumptions
- The channel encoding, exposure and calibration must be comparable. A scalar channel residual is not a perceptual color difference, complete color correction or conservation assessment.
- 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 observations and the complete conservation, lighting or transport assessment. Check material response, geometry, history and actual condition before applying local ratios, exposure terms or labels to an object.
References
Similar or alternative tools
- Exhibit Cumulative Light Dose Step
Add supplied illuminance exposure to a cumulative lux-hour record.
- Display Spectrum Weighted Band Dose
Calculate a supplied sensitivity-weighted multiband exposure term.