Print vs Screen Color Gamut Warning (Simplified) implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t7-067

Effect

Computation or source lookup only

Input and validation requirements

The specification does not provide a numeric gamut-boundary formula, lookup-table contents, branch threshold, desaturation formula, channel range, or channel-order declaration. Therefore deterministic expected outputs cannot be generated for general RGB inputs; black can additionally trigger 0/0 in a conventional saturation calculation.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "rgb": [
      255,
      255,
      255
    ],
    "encoding": "8-bit sRGB"
  },
  "expected_outputs": {
    "warning": "in-gamut",
    "provisional_hsv_saturation": 0,
    "suggested_desaturation_fraction": 0,
    "suggested_desaturation_percentage_points": 0
  },
  "reference_data": {
    "sRGB_white_encoded": [
      255,
      255,
      255
    ],
    "sRGB_channel_range": [
      0,
      255
    ],
    "source_convention": "IEC 61966-2-1:1999 standard sRGB encoded endpoint",
    "provisional_saturation_limit": 0.95,
    "limit_source_convention": "not a published standard table value; provisional instrument parameter"
  },
  "working": "max=255, min=255. S=(255-255)/255=0/255=0. Since 0<=0.95, result=in-gamut. Suggested desaturation=max(0,0-0.95)=0, or 0 percentage points."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json