The act of turning black in colour; a black stain or mark.
The result is that so long as the fillets are hot they are kept from contact with the air and blackening of the metal is prevented.
The eyes, with very few exceptions, are black, large and of a long almond-form, with long and beautiful lashes, and an exquisitely soft, bewitching expressioneyes more beautiful can hardly be conceived: their charming effect is much heightened by the concealment of the other features (however pleasing the latter may be), and is rendered still more striking by a practice universal among the females of the higher and middle classes, and very common among those of the lower orders, which is that of blackening the edge of the eyelids both above and below the eye, with a black powder called kohl (Lane, Modern Egyptians).
Abney and Baker have shown that the pure dry chloride does not blacken when exposed in a vacuous tube to light, and that the blackening is due to absorption of oxygen accompanied by a loss of chlorine.
The oil retained traces of sulphur, which showed themselves disagreeably in the smell of soaps made from it, and in the blackening of substances with which it was used.
The metal should be fire resistant and free from scorching or blackening - cast iron is usually the best option.