Manganese Blue was available from the 1930s to the 1990s, when manufacturing ceased due to the hazardous chromic acid process required for its production. Its discontinuation caused significant distress among watercolourists who valued its unique granulating transparency — properties no available substitute fully replaces.

Nostalgically mourned and technically irreplaceable. Manganese Blue represents the category of colours that are simply gone — discontinued for practical reasons, leaving an aesthetic gap that approximations cannot fill. Its loss is a reminder that the artist's palette is not permanent but subject to industrial and environmental pressures.

The discontinuation of Manganese Blue sparked one of the most sustained campaigns in the art materials industry — watercolourists petitioned manufacturers for decades. The colour's loss illustrates how dependent artists are on industrial chemistry and commercial decisions. Several manufacturers have attempted "Manganese Blue Hue" substitutes, but none fully satisfy those who remember the original.