Converting colours between systems

Transferring a colour from one system to another rarely produces an exact match. There is, however, almost always a good approximation. We use colour instruments to measure how close that approximation comes and how large the deviation is, so that you know where you stand before anything goes into production.

In practice, the request to convert a colour almost always comes from the same corner: a supplier works with one system, or does not know that other options exist.

“That isn’t possible” usually means “I’d rather not”

Powder coaters can supply NCS colours and RAL Design colours perfectly well. They often charge extra for it, and sometimes you are told it cannot be done — but it can. PPG, AkzoNobel, Van Wijhe Verf and other paint suppliers and powder coaters can make any colour.

So do not let yourself be sent back to a standard range because that is easier for the supplier. What is reasonable: a colour outside the standard costs more, and in small quantities that weighs more heavily.

Why a conversion is never exact

Colour systems are built up in different ways. The RAL Design System plus and RAL Effect are fixed in the CIELab colour space and are therefore measurable: every colour has a Lab value. RAL Classic grew historically and is not systematically built up — those 216 colours do not sit on a grid.

On top of that, a colour behaves differently on each material and in each finish. The same formulation gives a different result in powder coating than in paint, and the gloss level changes how saturated a colour looks. A conversion that is right on paper can still deviate once it is executed.

So always judge a physical sample in the final finish, and preferably alongside the colour you are trying to approximate. A screen is unsuitable for this.

Calculate it yourself, or have it measured

The conversion tool on this site does the arithmetic straight away: enter a RAL code, NCS notation, Pantone number or hex value and see what comes closest in the other systems, with the colour difference in ΔE2000.

What a calculation cannot do is judge. Where it concerns a façade, a product line in which parts sit side by side, or a colour that cannot be put right after delivery, we read the source colour with a colorimeter, find the best-fitting equivalent and say whether the difference will be noticeable in your application. Send us the source colour and the target system.