The technical aspects of photography obscure the general public's understanding of what is really happening in the photographic process. This workshop helps people to understand on the one hand the splitting of light into its different wavelengths and on the other hand the chemical background to photography.

The chemical basis of photography originated gradually at the end of the 18th century. The light-sensitive materials that allowed photographs to be made were produced first. In the first half of the 19th century people learned how to fix pictures, thus enabling them to be preserved.


In this workshop we make the colour pigments chemically. The pigments are selected so that when different agents are added to the same starting material the three different Heureka colours (blue, red and yellow) are obtained.

Blue: NH4Fe(SO4)2 + KFe2(CN)6 => KFe2 (CN)6 + K2SO4 + NH4KSO4

Yellow: NH4Fe(SO4)2 + Na2SiO3

Red: NH4Fe(SO4)2 + Fe3

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