The cyanotype is an alternative photography process discovered in the 19th century. This technique uses two mineral coumpounds - ferric ammonium citrate(NH₄)₅[Fe(C₆H₄O₇)₂] and potassium ferriacyanide K₃[Fe(CN)₆]. Mixed with water in equal parts and then combined together, the obtained solution is photosenzitive - once exposed to the UV light, it turns into the most vivid shades of blue. Also, the exposure time and the UV intensity are directly influencing the shades of blue, which is why our prints may vary in color - from light to dark blue.