RAL Classic Nearest Match Lookup

Approximate nearest caller independently verified RAL Classic swatches in same-white Lab, not paint-formulation match. Explicit declared color space/reference and caller applicability; not spectral equivalence, pigment mixing, press readiness or accessibility certification.

Description

RAL matching requires an identified swatch edition and comparable color measurements.

RAL matching requires an identified swatch edition and comparable color measurements.^[1]

The nearest caller-supplied Lab swatch is an approximation rather than an official RAL conversion. Use RAL Classic Nearest Match Lookup to find nearest supplied Lab swatches.

When to use RAL Classic Nearest Match Lookup

Use RAL Classic Nearest Match Lookup to find nearest supplied Lab swatches. Supply the intended palette IDs and Lab swatches under one common reference convention, then enter the query in that same coordinate system.

How to use RAL Classic Nearest Match Lookup and understand its results

Supply the intended palette IDs and Lab swatches under one common reference convention, then enter the query in that same coordinate system.
Enter Caller verified ral ids, Caller same white ral lab swatches, Query same white lab using the field table and validation rules below, then run the tool.
Read Nearest caller ids, Minimum declared space distance; interpret the units, signs, ordering and unknown-value placeholders described below.
Correct reported input errors and rerun. Apply successful results according to their specific meanings and check the assumptions before using them in a decision.

Input field	Meaning	Value type	Requirement
callerVerifiedRalIds	Caller verified ral ids	array of string	Required; constraints below
callerSameWhiteRalLabSwatches	Caller same white ral lab swatches	array of array	Required; constraints below
querySameWhiteLab	Query same white lab	array of number	Required; constraints below

Provide unique nonblank caller swatch IDs of at most 128 UTF-16 code units, one finite three-component Lab swatch per ID and a finite three-component query. The registry must be nonempty and all coordinates must use the same independently established white/reference convention. Calculate Euclidean distances and return every ID whose distance is exactly the minimum, preserving caller order. Ties use exact numeric equality. No named palette, RGB conversion, white adaptation or official matching certification is supplied.

nearest IDs = all caller IDs with distance==min(hypot(L−Lq,a−aq,b−bq))

Use the field order, units and branch conditions described above.

Output field	Meaning	Value type
nearestCallerIds	Nearest caller ids	array of string
minimumDeclaredSpaceDistance	Minimum declared space distance	number

json

{
  "input": {
    "callerVerifiedRalIds": [
      "a",
      "b"
    ],
    "callerSameWhiteRalLabSwatches": [
      [
        50,
        0,
        0
      ],
      [
        50,
        3,
        4
      ]
    ],
    "querySameWhiteLab": [
      50,
      3,
      4
    ]
  },
  "output": {
    "nearestCallerIds": [
      "b"
    ],
    "minimumDeclaredSpaceDistance": 0
  }
}

Limitations and assumptions

The nearest caller-supplied Lab swatch is an approximation rather than an official RAL conversion. Apply the exact scope and assumptions explained above.

All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse arrays fail validation. Domain-specific bounds, alignments and supported tokens are explained above; extremely large inputs or outputs can also be rejected. Input errors differ from successful false results, empty match lists and unknown-evidence placeholders.

Alternative or Complementary methods

Use Pantone Nearest RGB Lookup for a related task: Pantone approximations need a particular reference and comparable swatch measurements.

Use X11 Nearest Color Name Lookup for a related task: An X11 color-name match requires a particular palette and coordinate convention.

References

RAL Classic Nearest Match Lookup — tool.io

Similar or alternative tools

Pantone Nearest RGB Lookup
Pantone approximations need a particular reference and comparable swatch measurements.
X11 Nearest Color Name Lookup
An X11 color-name match requires a particular palette and coordinate convention.