Red blood stone

Description

The red blood stone is a red yellow earth, also called, red of Antwerp, red of Holland, red of Prussia, red ground, red chalk, sigilée ground, sinopite,…

it is a ferruginous clay, argillaceous ground, coloured by iron oxide, characterized on the chromatic level by ferric iron oxides.

The layer of ochers are numerous but the natural red blood stones are rarer. The France, the Germany and the Italy produce some.

Vitruve mentions the usta which is yellow ocher thus burned red color and Pline uses this term for minium and the red blood stone. The classic authors often mention a red ground called the sinopis coming from the town of Sinope.

Composition

Carractérisée on the chromatic level by ferric iron oxides. For the red blood stone, the hematite of FeO formula. Ochers can contain impuretées, nature and the proportion of these last depends on the source of the grounds. The red blood stones pouvent being natural or produced by calcination of yellow ocher. The hydrated ferric oxide is dehydrated with the top of 250C°. The degree of temperature influences the composition of the red blood stone. Ochers whose calcination temperature did not exceed 250°C reabsorb water once exposed to the humid air.

Preparation

According to Pline, the red blood stone manufactured by calcining yellow ocher in pots nine, is luted argil on their circumference. It specifies that more it burned on the hearth better it is. Vitruve mentions that the red blood stone was calcined until extinct incandescence then brutally in vinegar.

Use

Used for all techniques of painting.

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