Method
What a record is
Every entry in the colour reference is a record: one engine family, one market, one division where the badge changed the colour, one span of years, one component. The MGB's B-series block from 1962 to 1971 is one record. Its rocker cover, if a source says it differed, is another. Records are grouped on the page for the engine family, because colour followed the engine and the era rather than the car.
Where the data comes from
Sources are listed on every record, and each carries a type: factory (workshop manuals, parts books, heritage archives), club (owners' club technical committees and judging standards), archive, community, forum or retailer. For most British engines no factory document on colour has been found, and what is known lives in forum threads where owners describe the engines they have stripped. Those threads are cited, and a record that rests on them is graded C and says so. A thread is never treated as a factory document, and where a record leans on a single account its notes say that too.
Facts are not copyrightable. A club's write-up is. We take the fact and write the sentence fresh.
Confidence grades
- A, factory documented. A workshop manual, parts book or heritage archive states the colour.
- B, club verified. An owners' club technical committee or a published judging standard states it.
- C, community consensus. Two or more independent restorer sources agree.
A separate flag, Disputed, is set whenever sources conflict, whatever the grade. Two factory documents can disagree. When they do, the record says so, gives each position, and says what would settle it. Being explicit about disputes is the point; it is what a forum thread cannot do.
Measurement
Where an unfaded original exists, a sprayed reference swatch is measured with a handheld spectrophotometer and the Lab* reading is stored on the record. The colour patch you see on the page is derived from that reading, never typed in. Candidate modern products are sprayed to the same protocol and measured too, and the difference is published as ΔE (CIEDE2000). Under 1 is not visible; 1 to 2 is visible side by side; 2 to 3.5 is visible at a glance; above 3.5 is a different colour. Those bands are guides, not law.
A record does not wait for measurement to publish. Until it is measured it says so, and the patch it shows is labelled approximate: the colour its name describes, taken from the name and not from a reading, with no Lab* beside it. Your screen shifts it again. The measured patch replaces it.
Instrument, illuminant and observer angle are recorded here once the first swatches are measured.
Corrections
Every record carries a public history: date, what changed, and the source. Corrections are welcome and are logged the same way. If you have a factory document or a club standard that contradicts a record, the form on each page is the way to send it.