chrome

Used as a mordant in dyeing cotton.  Use is now limited because it may, if used to dye fabric for clothing, cause skin allergies.  These adverse effects are eliminated when chrome is used in association with formic acid while enhancing its fastness properties.  The most common chrome mordants are bichromate of potash, potassium dichromate or sodium dichromate.  These mordants are light sensitive and must be kept in dark containers.  See chrome dye.