Recreating the Medieval Palette
In February this year the British Library hosted a course called ‘Recreating the Medieval Palette’ run by pigment expert Cheryl Porter who is also Director of the Montefiascone Project and a freelance conservator. Those of us attending were a small group of conservators and material specialists from the British Library and other institutions hoping to deepen our knowledge of the materials we work with. The course was an interesting mixture of theory and practice, with the morning lectures covering the basic colour groups and the afternoons providing a more hands-on approach giving us the opportunity to prepare and paint out the pigments and inks on a variety of papers and parchment.
Alongside the history and manufacturing processes of the pigments we learnt about their chemical composition, visual characteristics, behaviour in response to their environment and modes of deterioration. This is essential background knowledge when undertaking a conservation treatment.
The medieval alchemists didn’t worry too much about health and safety in their search for vivid and enduring colours; hence the highly poisonous production methods for concocting pigments such as lead white, red lead, lead tin yellow, verdigris and cinnabar/vermilion. When preparing the pigments for painting, the powder has to be mixed with a binding medium to give viscosity and adhere it to the page. We experimented with different binding agents – egg white and gum arabic – which changed the working characteristics of the pigments when painted out.
Making some of the lake colours provided an opportunity to see some real alchemy. A lake is a dyestuff made from organic matter which is precipitated onto a colourless mineral base. Plants such as buckthorn, weld and saffron were used to make a variety of colours, and insects such as kermes and cochineal produced shades of red.
Left: Experimenting with mixing saffron (yellow) with verdigris (green). Right: Painted-out medieval blues; the brighter colours are mineral-based azurite and ultramarine and the subtler shades, indigo and woad
We also had an opportunity to learn about inks used in manuscripts. This was extremely interesting from a conservator’s point of view as we discovered that inks can often be identified by the way in which they deteriorate over time. The earliest writing implements were reed pen and quill, and the group’s attempts at writing with these proved that both skill and practice were required!
At the end of this highly informative and entertaining week we went away having learnt a lot from Cheryl’s wealth of knowledge and experience, as well as having enjoyed stories of her adventures collecting and researching pigments. Our array of sample sheets will also provide a valuable visual and chemical reference for identifying pigments in the future.