Many of the materials and methods of working used by Helen are the same as (or very similar to) those used by medieval artists.
Gold - The use of gold in manuscripts gives us the term ‘illumination’, which refers to the way a page is lit up when the gold catches the light. Gold was used to the glory of God to adorn the pages of many manuscripts, emphasising the importance of the words contained in the book.Gold can be used in two forms: as fine leaves or as a powder.
Gold leaf needs to be ‘stuck’ in some way, and there are a variety of substances (called mordants) to which it can be applied. The most widely used mordant in medieval manuscripts was gesso, a mixture made of plaster, white lead, fish glue and sugar. This is applied to the area to be gilded and left to dry overnight. Once any imperfections have been smoothed out, the gesso is breathed on, which slightly reactivates the glue and sugar, and the gold leaf applied. It is then burnished with an agate burnisher the bring up the brilliant, mirror-like shine.
This type of gesso cannot be bought and needs to be made by the illuminator by grinding the ingredients together using a pestle and mortar for about an hour. There is nothing ‘instant’ or ‘easy’ about this work: if you wish to achieve the special quality of this type of gilding, you must be prepared to put in the time and effort!
Gold powder - leaves of gold can be ground to a fine powder, mixed with a gum and applied with a brush. This form of gold is called ‘shell gold’ because traditionally it was made and sold in shells.
Vellum - most of the manuscripts made in medieval Europe were written on calfskin vellum, which is why they have lasted so well, retaining the vibrancy of colour along with the richness of their gold decoration.
Painting on vellum gives the paint a luminosity which is not possible on paper; the paint sometimes appears to ‘float’ on the surface.