Important: Safety Warning
This page contains a formula or preparation using substances now known to be dangerously toxic, such as arsenic, mercury, lead, or cyanide compounds. Exposure to these substances can cause severe poisoning, permanent injury, or death.
In addition, this page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
This information has been left in for historical purposes but should not be acted upon.
Chrome Red
Melt saltpetre in a crucible heated to dull redness, and adl chrome yellow, by small portions, till no more red fumes arise. Allow the mixture to 100 parts boiling water, and, whilst boiling, let the verdigris pulp be gradually added, constantly stirring the mixture till the precipitate becomes a heavy granular powder. It is, on the whole, a permanent color. It should not settle, then pour off the melted salt from the be used with cadmium yellow, as that is a heavy sediment, and wash the latter with sulphide, and with it forms sulphide of copper, water, which should be quickly poured off, which is brown. It is a good oil pigment and dry the pigment. The liquefied salt when properly used; it has but little body. poured off contains chromate of potash, and It answers well in water-color painting; it is reserved for making chrome yellow. 2707. Orange Chrome is chrome yellow acted on by an alkali, which deprives it of part of the chromic acid. All the chromes are chromates of lead, and are therefore liable cannot, however, be used in fresco or silicious painting.