COLOUR
How colour matching works, and why a code is only the start
A paint code identifies what left the factory. It does not identify what is on the vehicle in front of you, and the gap between those two things is where most colour disputes live.
1 · What a code actually records
A manufacturer paint code is an index into that manufacturer’s colour system for a given model and period. Refinish manufacturers then publish mixing formulas against those codes, so a shop can reproduce the colour from toners it already holds. The code is a pointer to a formula, not a measurement of a surface.
That distinction matters because the same code can point to different formulas in different markets and different years, and because older codes sometimes survive only in one refinish system’s database and not in others.
2 · Variants, and why they exist
Factory colour is not perfectly constant. Different assembly plants, different suppliers and normal production tolerance mean that one code can cover a spread of slightly different results. Refinish systems respond by publishing variants — several alternative formulas for a single code — and the shop’s job is to pick the one that matches the actual vehicle.
Then the car ages. Ultraviolet exposure, washing, polishing and previous repairs all move the surface away from the day it was painted. A perfect match to the original formula can be a visible mismatch on a ten-year-old panel, and this is not a fault in the formula.
3 · Metamerism
Two surfaces can match under one light source and differ under another, because they reach the same appearance through different pigment combinations with different spectral behaviour. This is metamerism, and it is why a match approved under shop lighting can fail in daylight.
The practical defence is to assess a match under more than one light, including daylight, and to prefer a formula built from pigments similar to the original where that is known. A close match by numbers is not automatically a close match by eye.
4 · Effect finishes make it harder
Metallics, pearls and colour-shift finishes change with viewing angle, so they cannot be described by a single measurement. They also depend on application: flake orientation is set by the gun, the distance, the film build and the flash time, which means two shops spraying identical material get different results.
For these finishes a sprayout card is not a nicety. It is the only reference that can settle an argument later, and it should be made with the same equipment and technique that will be used on the job.
5 · Establishing a usable reference
In rough order of reliability: a manufacturer code with the vehicle, year and market; a spectrophotometer reading of a clean, unrepaired, undamaged panel; a removable painted part such as a fuel flap sent for matching; and finally a photograph, which is a conversation starter rather than a reference — screens and lighting make it unusable as a measurement.
Whichever you have, keep a sprayout from the approved batch. If a later order has to be checked against it, that card is the only evidence anyone will accept.
NEXT STEP
Send the vehicle, year, market and the best reference you hold, and we will investigate what formula or material exists for it.