"Bartholomew is best known for the development of colour contouring (or hypsometric tints), the system of representing altitudes on a graduated colour scale, with areas of high altitude in shades of brown and areas of low altitude in shades of green. He first showcased his colour contouring system at the Paris Exhibition of 1878; although it initially met with skepticism, it went on to become standard cartographical practice". However, he might have picked up this idea during his time in Gotha as the colour scheme was first introduced by Emil von Sydow (1812–1873) in 1838 when he developed a color methodology for landscape features using hachures, where green was depicted for lowlands and brown used for highlands. The white for the higher reaches might later have been used by Hermann Haack (1872–1966) for his Perthes' wall maps.