Quir Bouilli (boiled leather) is a leather hardening technique that was used to make armour and other objects throughout the Middle Ages. It involves boiling and shrinking leather fibres so that they become denser and harder. Whilst the leather is wet it can be moulded in to any shape which it then retains once dried. The leather used for this process is vegetable tanned, this means it is tanned using natural organic matter such as tannic acid; a plant extract found in Oak and Mimosa trees.
We combine this moulding process with another ancient process: Iron Gaul Ink. Iron Gaul Ink was the most commonly used writing ink from the 5th century to the 19th century and is made through a natural chemical reaction. A reaction takes place when iron and tannic acid are combined which produces a blue ink. During our making process after the vegetable tanned leather is boiled, residual tannic acid rises to the surface of the leather. By laying iron filings on top of the leather and resting them wet for 48 hours the same chemical reaction occurs producing small pockets of soluble blue ink. These seep through the surface of the leather dying it permanently.
Benjamin John Hall studio made 38 paper pattern variations, 42 paper mock ups and 27 finished prototypes over a period of 3 years to research, design, develop and finalise these complex objects. Cuir Bouilli is entirely made in London.