In 1927 the German Reichs-Ausschuß für Lieferbedingungen und Gütesicherung (Imperial Commission for Delivery Terms and Quality Assurance) invented a collection of 40 colours under the name of "RAL 840". Prior to that date manufacturers and customers had to exchange samples to describe a tint, whereas from then on they would rely on numbers. 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 colors and is in use to this day. In the 1960s the colours were given supplemental names to avoid confusion in case of transposed digits