Blue back charts

From the eighteenth century, navigators relied on nautical charts produced by a handful of chart makers and instrument sellers who worked in the City of London. These privately produced charts, or bluebacks as they were known from the tough blue manilla paper on which they were mounted, were in circulation amongst the merchant fleets of the World until the Second World War.
The story of private chart making is also more or less the history of James Imray, Laurie, John William Norie and Wilson Ltd, which is the descendent of the old publishing firms and to this day flourishes as the leading private publisher of nautical charts and pilot books.
Other publishers who published blueback charts are Mount and Page, Robert Sayer, John Hamilton Moore, Robert Blachford, William Heather, David Steel, R. H. Laurie, and John Hobbs, among others.
Bluebacks became so popular that chart makers outside of England, including America, Netherlands, Scandinavia, France, Germany, Russia, and Spain produced them until the late 19th century.
