Source: https://guthlabs.ai/docs/instruments/blackbody-color-temperature-rgb-approximation/implementation/

instrument implementation / implementation-contract

# Blackbody Color Temperature → RGB Approximation implementation

A source-bound implementation contract for Blackbody Color Temperature → RGB Approximation; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## 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**: t5-034

**Effect**: Computation or source lookup only

## Input and validation requirements

The approximation has an observable discontinuity at the t = 66 branch boundary: 6600 K produces approximately (255,255,253), while 6601 K produces approximately (255,252,255). Inputs at or below 0 K also reach ln(0) or an invalid logarithm and must be rejected.

## 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": {
    "temperature_K": 1000
  },
  "expected_outputs": {
    "R": 255,
    "G": 68,
    "B": 0
  },
  "working": "t=1000/100=10. R=255 because t<=66. G=99.4708025861*ln(10)-161.1195681661=99.4708025861*2.302585093-161.1195681661≈229.03999-161.11957=67.92042→68. B=0 because t<=19. Result=(255,68,0)."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/blackbody-color-temperature-rgb-approximation/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/blackbody-color-temperature-rgb-approximation/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/blackbody-color-temperature-rgb-approximation/qualification/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json`

- `evidence-tranche5/tranche5-results.json`