From 1862, and as in France at the same time, the Bank of Algeria adopts the process of printing in color "celestial blue" in order to anticipate possible counterfeits by photographic reproduction.
The first Algerian notes denominated in francs issued between 1851 and 1870 are particularly rare and never appear on sale. These banknotes are unfortunately not yet listed in the catalog Numizon but have been the subject of a catalog book published in 2016 by Maison Palombo and titled: "Banknotes Bank of Algeria, Volume 1, 1851-1870".
These notes circulated until the beginning of the 20th century, before being gradually replaced by the first two-color notes of 1912 and the polychrome banknotes of the 1920s.