This enamel-coated, cast iron bathtub is a typical example of a sanitary device produced in the first half of the previous century. Bathtubs of cast-iron, i.e. a high carbon alloy of iron and carbon, and of ceramic gradually replaced the wooden and sheet-metal tubs used for bathing. That resulted from the development of modern water supply and sewerage networks in many cities. The process of enamel coating of iron and steel, which involves covering a surface with a powder and baking it at high temperatures until a uniform layer of glaze forms, was developed by David Dunbar Buick in around 1887. Today’s bathtubs are usually made of fibreglass or acrylic, which allows complex shapes to be formed that would be difficult to create using different materials. Acrylic was first used in the production of bathtubs in 1979 by brothers James and Richard Wheeler. The bathtub presented here comes from an apartment in a tenement house in Studencka street in Kraków.
Interesting fact: the first vessel that was documented to have a bathing function is considered to be a stone bathtub of the 16th century BC, located in the Royal Palace in Knossos on Crete.

References:
Historia wanny z kąpielą w tle, dom.wmw.pl web portal 15.06.2016, http://dom.wm.pl/363971,Historia-wanny-z-kapiela-w-tle.html (Accessed: 9.05.2021).
Who remembers David Dunbar Buick?, “Pre-war Buick” blog, http://www.prewarbuick.com/features/who_remembers_david_bunbar_buick (Accessed: 9.05.2021).