RAL colour standard relates to the shade of the colour: This collection, which follows the naming of RAL Classic, was invented in 1961. It is nowadays 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. 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
Pale crag martin often treated as the small, pale northern subspecies of the rock martin, but it is now usually considered to be a separate species. The changes in size and colour are continuous, so the evidence for separate species is not strong, although some rock martins can weigh more than twice as much as the smallest subspecies of the pale crag martin. The average weight for "P. o. fusciventris" is 22.4 g (0.79 oz) against 10 g (0.35 oz) for "P. o. obsoleta". There do not appear to be any intermediate forms where pale crag martins and rock martin populations breed close