Light Red

Synonyms:

Light Red, Burnt Ochre, Rouge Anglais, Brun Rouge, Englischrot

Light red is, or ought to be, yellow ochre burnt - that is, calcined. The different varieties of yellow ochre yield, as might be expected, products having various hues and tints of this rather pale and dull brownish or orange red. Moreover, these hues depend in some measure upon the temperature at which the calcination is effected. To prepare light red, the selected yellow ochre is usually crushed and then roasted on an iron plate heated to redness. When the desired tint has been attained the material is thrown into cold water, ground, and washed. Light red may also be made by conducting the finely-divided yellow ochre suspended in a current of air into a heated chamber or furnace. Light red consists, then, of yellow ochre deprived of its water of hydration by means of heat. It is necessary to employ yellow ochre as free as possible from organic matter and from lime if a bright-coloured product be desired.

Light red possesses a considerable degree of opacity. Its hue may be defined as a scarlet, modified by a little yellow and grey. It is perfectly permanent and without action upon other pigments.

Light red boiled with hydrochloric acid will, if genuine, yield a solution, which after filtration will give no precipitate, but merely a slight cloudiness, on the addition of a few drops of barium chloride solution. The terms 'rouge Anglais' and 'Brun rouge' are not infrequently applied to artificially prepared iron reds.