by Daniel Sanchez Villavicencio, PhD student in History of Art.
As part of the activities organised by the Scotland Group of the Institute of Conservation (ICON), the Centre for Textile Conservation and Technical Art History (CTCTAH) of the University of Glasgow had the pleasure of hosting a 3-day practical gilding course, between the 3rd and 5th of September 2018
Taught by the head frames conservator of the Royal Museums Greenwich, Tim Ritson, and attended by a diverse group of 11 conservators and 2 students from Australia, Canada, England, France, Mexico, Northern Ireland, Norway, Scotland and Wales, the course aimed to familiarise the participants with the materials and techniques of the two traditional methods of gilding: water based, and oil based.
Gilding is simply defined as the decorative technique of applying a fine gold leaf to a surface, but the method for achieving it is far from being simple. With an arrangement only comparable to that of a “Hogwarts lesson”, the tutor laid on the table a curious set of tools, coloured powders, different liquids and what appeared to be small cauldrons, all of which we would eventually got acquainted with. Oil gilding uses a very thin layer of gold size to adhere the gold leaf, -usually containing pre-thickened linseed oil, copal resin and turpentine in the mixture-, suitable to be applied onto any material, both indoors and outdoors. Water gilding is slightly more complicated and only fit for indoor use; needing a previous layer of rabbit skin glue as sealant, a number of nicely smoothed coats of gesso (mixture of rabbit skin glue and chalk), and a very thin layer of clay or bole to receive the gold leaf. This laborious layering system is rewarding, as the resulting surface can be burnished with agate or dog’s tooth burnishers, achieving the mirror-like appearance that only water gilding can provide.
The course was impeccably set up, with a carefully prepared gilding box for each participant, containing a gilders cushion, a tiny squirrel’s hair gilders tip and fine brushes, a gilders knife and a square-shaped gold leaf book of 23 karat. All of these would be used for gilding different objects, including a plaster shell, two different mouldings and the pièce de résistance, our very own wooden frame. Each of them allowed the practicing of both gilding techniques, comparing their advantages and difficulties, whilst testing our manual skills and even the ability to maintain a calm breathing, as the delicate gold leaf seemed to vanish into dust with the slightest breeze.
As a former technical art history student and current researcher on the making of painted banners, the course allowed me to better understand the possibilities and consequences that the two techniques have for the materiality of an object. Since painted banners were designed to be held aloft in the demonstrations they were made for, it is only fair to suggest the use of an oil-based technique for applying the metal leaf on their decorations, an assumption that will have to be confirmed or refuted with the proper technical analysis and material reconstructions. In this way, the course had an immediate impact on a particular research subject, but also, as any of the participants would agree, it enriched the knowledge about a widely used decorative technique, proving as ever that ‘every day is a school day’.