CRI Calculation

Restricted CIE13.3generalCRI Ra=mean R1…R8from actual already independently chromatic adapted ΔEi(1964U*V*W*), Ri=100−4.6ΔEi. Does not compute spectral integration/adaptationfromSPDs, nofullCRIor light-safety certificate.

Description

General CRI Ra averages the first eight test-color indices after independently completed color adaptation.

General CRI Ra averages the first eight test-color indices after independently completed color adaptation.^[1]

This tool converts supplied adapted differences to Ra without performing spectral integration or a full CRI workflow.

When to use CRI Calculation

Use this tool to convert supplied adapted differences to Ra without performing spectral integration or a full CRI workflow.

How to use CRI Calculation and how it works

Prepare actualIndependentlyCieAdaptedFirstEightTestColorDifferences, with the units, conventions and assumptions below.
Enter the required fields and run CRI Calculation.
Read result.value using the output definitions below.
Correct any rejected inputs and rerun; interpret the result within the stated model and its assumptions.

Input field	Meaning	Value type	Requirement
actualIndependentlyCieAdaptedFirstEightTestColorDifferences	Exactly eight nonnegative adapted test-color differences in the intended CRI convention.	array of number	Required; other constraints below

Supply exactly eight nonnegative adapted sample color-difference values in the intended CRI convention. Compute each R_i=100-4.6*deltaE_i and average them for Ra. Negative scores are retained without clamping. The tool does not perform spectral sampling, reference-illuminant selection or chromatic adaptation.

Ra=mean_{i=1..8}(100-4.6*deltaE_i)

Apply the input ordering, units and branch conditions stated above.

Output field	Meaning	Value type
result	Object containing the calculated or selected fields below.	object
result.value	Mean of eight adapted sample color-rendering scores; negative values are retained.	number

json

{
  "input": {
    "actualIndependentlyCieAdaptedFirstEightTestColorDifferences": [
      1,
      1,
      1,
      1,
      1,
      1,
      1,
      1
    ]
  },
  "output": {
    "result": {
      "value": 95.39999999999999
    }
  }
}

Limitations and assumptions

The calculation uses the supplied observations and model inputs. It does not collect measurements, select a reference population or coefficient, or establish that the model applies to the actual case. The stated branch conditions and output units remain part of the result.

All fields require explicit values. Unexpected fields, wrong types, nonfinite numbers and sparse arrays are rejected. Alignment, bounds and supported-token rules are explained above; extremely large inputs or nonfinite results can also fail. Input errors differ from successful false comparisons, unavailable-domain flags and empty match lists.

Alternative or Complementary methods

Use White Balance Gain Calculator for a complementary operation: Neutral-patch white-balance gains operate on linear channel values under a consistent exposure and black-level convention.

Use Color Correction Filter Factor Calculator for a complementary operation: A measured filter factor compares reference and filtered signals under matched illumination and channel conditions.

References

CRI Calculation — tool.io

Similar or alternative tools

White Balance Gain Calculator
Neutral-patch white-balance gains operate on linear channel values under a consistent exposure and black-level convention.
Color Correction Filter Factor Calculator
A measured filter factor compares reference and filtered signals under matched illumination and channel conditions.