RAL colour standard

In 1927, the German group Reichs-Ausschuß für Lieferbedingungen (National Committee for Delivery and Quality Assurance) invented a collection of forty colours under the name of "RAL 840".[2] Prior to that date manufacturers and customers had to exchange samples to describe a tint, whereas from then on they would rely on numbers.[3]

In the 1930s the numbers were changed uniformly to four digits and the collection was renamed to "RAL 840 R" (R for revised). With tints constantly added to the collection, it was revised again in 1961 and changed to "RAL 840-HR", which consists of 210 colours and is in use to this day. In the 1960s the colours were given supplemental names to avoid confusion in case of transposed digits. At the international furnishing fair imm Cologne, 13 till 19 January 2020, two new colours were presented in the Classic Collection: RAL 2017 RAL Orange and RAL 9012 Clean Room White.[4]

As "RAL 840-HR" covered only matte paint the 1980s saw the invention of "RAL 841-GL" for glossy surfaces, limited to 193 colours.[5] A main criterion for colours in the RAL Classic collection is to be of "paramount interest". Therefore, most of the colours in it are used on warning and traffic signs or are dedicated to government agencies and public services (for example: RAL 1004 - Swiss Postal Service, RAL 1021 - Austrian Postal Service, RAL 1032 - German Postal Service).[6] The first digit relates to the shade of the colour:

This collection, which follows the naming of RAL Classic, was invented in 1984. It is now made up of ten colours (RAL 1039-F9 Sand beige, RAL 1040-F9 Clay beige, RAL 6031-F9 Bronze green, RAL 6040-F9-Light olive, RAL 7050-F9 Camouflage grey, RAL 8027-F9 Leather brown, RAL 8031-F9 Sand brown, RAL 9021-F9 Tar black and RAL 6031-HR Bronze green for non-camouflage applications), used by the Bundeswehr for military camouflage coating.[7][8]

In 1993, a new colour matching system was introduced, tailored to the needs of architects, designers and advertisers. It started with 1,688 colours and was revised to 1,625 colours and now 1825 colours. The colours of RAL Classic and RAL Design do not intersect.

Contrary to the preceding systems, RAL Design features no names and its numbering follows a scheme based on the CIELAB color space, specifically cylindrical CIEHLC. Each colour is represented by seven digits, grouped in a triple and two pairs, representing hue (000–360 degrees, angle in the CIELab colour wheel), lightness (same as in L*a*b*) and chroma (relative saturation). The three numeric components of almost all RAL Design colours are multiples of 5, the majority are divisible by 10.[9]

Conversion from RAL Design number tuple to CIELAB

${\displaystyle {\begin{aligned}{\text{RAL}}_{\text{Design}}&=\left(h_{ab}^{\circ },L^{*},C_{ab}^{*}\right)\\a^{*}&=C_{ab}^{*}\cdot \cos \left(h_{ab}^{\circ }\right)\\b^{*}&=C_{ab}^{*}\cdot \sin \left(h_{ab}^{\circ }\right)\end{aligned}}}$

"RAL 210 50 15" converts to L* = 50, a* = −12.99, b* = −7.5, for instance.

RAL Effect comprises 420 solid colours and seventy metallic colours. It is the first collection from RAL to be based on waterborne paint systems.

RAL Digital is software that allows designers to navigate the RAL colour space.