Print vs Screen Color Gamut Warning (Simplified)

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Audio, Music, Photography & Color

Tranche

tranche-7

Evidence ID

t7-067

Ledger rows

1

No ledger note is attached.

Review findings

The submitted honest-label warning is appropriate, but the implementation is not verifiable as specified because neither the lookup table nor the heuristic formula exists. Vendor must define and version the provisional rule, or require a selected ICC profile and implement a standard profile-based gamut check. The four expected outputs are deterministic only under the explicitly documented provisional HSV rule shown in unit_assumptions; they are not evidence that those colors are actually in or out of a particular CMYK press gamut.

Formula and scope findings

• No reproducible formula is specified: 'saturated RGB/CMY channel extremes' and 'typical press gamut boundary approximation' do not define a mathematical decision rule.
• No CMYK conversion, press condition, ink limit, paper white, profile, rendering intent, or gamut-boundary table is supplied. There is no universal CMYK/SWOP gamut boundary independent of an ICC profile.
• The suggested-desaturation output has no defined algorithm, scale, target gamut, or maximum adjustment.
• The test vectors below use an explicit provisional HSV-saturation heuristic only so that deterministic vectors can be supplied; this heuristic is not established by the submitted specification and must not be treated as a validated SWOP gamut test.

Unit assumptions

• Input RGB is three 8-bit IEC 61966-2-1 sRGB encoded channels in the inclusive range 0 through 255, not linear-light RGB.
• For the provisional heuristic, saturation is HSV saturation: S=(max(R,G,B)-min(R,G,B))/max(R,G,B) when max>0, and S=0 when max=0.
• The provisional boundary is S<=0.95 for in-gamut and S>0.95 for out-of-gamut; this threshold is dimensionless and is not a published CMYK gamut limit.
• Suggested desaturation is max(0,S-0.95), reported as a fraction and percentage points. This is a provisional convention, not a standard output.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

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.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "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."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

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

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json