RAL is a colour matching system used across European industry. Every colour carries a four-digit code — RAL 3020, RAL 7016 — and that code refers to one single, defined shade.
The first digit indicates the colour family: 1 yellow, 2 orange, 3 red, 4 violet, 5 blue, 6 green, 7 grey, 8 brown, 9 white and black.
The system's value is repeatability. "Traffic red" is open to interpretation; RAL 3020 is not — and a batch coated next year can be matched to one coated today.
The code specifies colour, not surface texture. The same RAL number comes in matte, semi-gloss and gloss, in smooth or textured versions, so gloss level has to be agreed separately.
One caution: both screens and printed swatch books shift colour. Before approving a shade for production, judge it from a coated sample panel under the actual light the part will live in.