The traditional surface for an egg tempera painting is wood - this is because egg needs a rigid support and will eventually peel off something like paper. To make the wood surface smooth enough for painting on, and to protect the artwork from the acid and oils in the wood, it must be prepared with an absorbent sort of plaster known as gesso. Gesso is made with an animal glue (such as fish glue, rabbit skin glue or gelatine) and a whiting made of finely ground chalk (calcium carbonate) or gypsum (calcium sulphate). (By the way 'gesso' is just Italian for gypsum). At this point, a word of advice for the beginner: if you are starting out and you just want half-a-dozen little boards for practising and learning on, then buy them from a supplier (some addresses on my useful supplier list). The process is time-consuming, fiddly, messy, requires workshop space and tools, and much patience and elbow grease. In times gone by an artist had minions in his workshop to do this sort of thing: the results of preparing boards in a small domestic kitchen tend to be catastrophic and put paid to normal culinary activity for a couple of days. However, if you plan to do a lot of painting, don't want to be constrained on size, or are economically minded, read on. There is also a printable version of the instructions (click link above).
First consider what material you will use for your support:
1. The traditional material for a medieval altar piece or icon is a properly cut and seasoned non-resinous wood which is readily worked: poplar, linden, birch. The face of it can be carved, routed out and shaped. Unless it is quite tiny it must be routed and braced on the back to prevent it warping or cracking when all the wet gesso is applied. This is what you see in medieval altarpieces and icons. This requires access to the right quality timber, specialist woodworking skills and tools: failing those, there are a few suppliers who will make a support to your specifications: names to follow)
2. The modern alternative is high-quality birch ply: this has the advantage of being lighter, not prone to warping, and preserves some of the practical characteristics and symbolism of wood (important to icon painters). Modern ply, bonded with superior glues, does not delaminate in the wet process of applying gesso, but avoid using what is called 'marine' ply, designed to be waterproof - you want the gesso to bond with the wood surface. A board made with ply is not as wonderfullly absorbent as a timber one is: this will only be a bother to devotees of the Russian float technique, ie that taught by the Prosopon School of Iconology. Carefully sand, stain and varnish the back and sides of your board unless you plan to frame it.
3. Many egg tempera painters use MDF board, known as Masonite in the US. Personally I don't like the stuff: it's quite heavy, it makes clouds of fluff when you saw it up, the edges fray and it swells up and falls apart if it gets wet. However, none of this matters at all if you are just studying, painting in a contemporary style, or are planning to frame. I have a 'quick and dirty' method for making student boards and the bits I use myself for try-outs - shortens the whole process considerably and saves a lot of hassle: scroll to the bottom of this page to read or print out instructions!
Now you will prepare your board for gessoing: (a printable version of these instructions here: a simple gesso board)
Bear in mind there are about as many methods for making gessoed supports as there are artists - everyone evolves their own proportions and refinements as they gather experience. These instructions give a basic flat board with gesso of average hardness and absorbency. A note for icon-painting students: it's always a good idea to make your boards to fit your drawings, rather than the other way round, as you will have more artistic control. However, certain proportions are standard: for half-figure icons use the proportion 3:4 (ie 20 cm wide, 25cm tall). For a Virgin and Child icon you may need a slightly wider board to accommodate the two figures. For a standing figure, use the proportion 1: 2 (ie 15cm wide by 30cm tall). Remember to allow for an appropriate border all around the icon - this is an important element of designing an icon.
Materials needed:
Method:
NB: it is important to avoid getting air bubbles in your gesso mixture. These cause pinprick holes in your finished board and spoil the surface of your painting or gilding later. Air bubbles are introduced by stirring too vigorously, over-heating the mixture or painting the gesso on too thickly.
And for the impatient or lazy, my super-quick board method:
Glue a piece of acid-free white mountboard (get offcuts from the framers) to your piece of ply or MDF: use woodworkers' PVA or hide glue. Weight it down under a pile of heavy books and allow to dry overnight. Trim mountboard flush with the board edges. Paint a size layer onto the card, allow it to dry, and paint with gesso as before - four or five layers will be enough. This will give you a super-flat surface for quick sanding, and is fine for practice pieces and beginners.
First consider what material you will use for your support:
1. The traditional material for a medieval altar piece or icon is a properly cut and seasoned non-resinous wood which is readily worked: poplar, linden, birch. The face of it can be carved, routed out and shaped. Unless it is quite tiny it must be routed and braced on the back to prevent it warping or cracking when all the wet gesso is applied. This is what you see in medieval altarpieces and icons. This requires access to the right quality timber, specialist woodworking skills and tools: failing those, there are a few suppliers who will make a support to your specifications: names to follow)
2. The modern alternative is high-quality birch ply: this has the advantage of being lighter, not prone to warping, and preserves some of the practical characteristics and symbolism of wood (important to icon painters). Modern ply, bonded with superior glues, does not delaminate in the wet process of applying gesso, but avoid using what is called 'marine' ply, designed to be waterproof - you want the gesso to bond with the wood surface. A board made with ply is not as wonderfullly absorbent as a timber one is: this will only be a bother to devotees of the Russian float technique, ie that taught by the Prosopon School of Iconology. Carefully sand, stain and varnish the back and sides of your board unless you plan to frame it.
3. Many egg tempera painters use MDF board, known as Masonite in the US. Personally I don't like the stuff: it's quite heavy, it makes clouds of fluff when you saw it up, the edges fray and it swells up and falls apart if it gets wet. However, none of this matters at all if you are just studying, painting in a contemporary style, or are planning to frame. I have a 'quick and dirty' method for making student boards and the bits I use myself for try-outs - shortens the whole process considerably and saves a lot of hassle: scroll to the bottom of this page to read or print out instructions!
Now you will prepare your board for gessoing: (a printable version of these instructions here: a simple gesso board)
Bear in mind there are about as many methods for making gessoed supports as there are artists - everyone evolves their own proportions and refinements as they gather experience. These instructions give a basic flat board with gesso of average hardness and absorbency. A note for icon-painting students: it's always a good idea to make your boards to fit your drawings, rather than the other way round, as you will have more artistic control. However, certain proportions are standard: for half-figure icons use the proportion 3:4 (ie 20 cm wide, 25cm tall). For a Virgin and Child icon you may need a slightly wider board to accommodate the two figures. For a standing figure, use the proportion 1: 2 (ie 15cm wide by 30cm tall). Remember to allow for an appropriate border all around the icon - this is an important element of designing an icon.
Materials needed:
- Board of wood or ply (1.2 - 2.2 cm thickness) cut to size and sanded
- Piece of butter muslin or similar lightweight cotton or linen cloth: the purpose of the cloth is to adhere the two disparate materials, wood and gesso, to reduce the grain of the wood, and provide a barrier to the lignin. It also holds the painting together if the wood support cracks.
- Whiting – available from art suppliers. A 500g packet will do quite a few boards – perhaps split a bag with a friend. Decorator's plaster is not suitable as the grains are too coarse. Plaster of Paris (dental plaster) is not the same thing.
- Powdered gelatine, any brand. Available in the 'traditional desserts' section of the supermarket. Not the vegan one!
- Emery paper, grades 240, 400, 600. Mixed packs are available from anywhere which supplies fine grade sandpapers for car body work (such as Halfords in the UK) - or buy on ebay.
- Wide decorator's brush
Method:
NB: it is important to avoid getting air bubbles in your gesso mixture. These cause pinprick holes in your finished board and spoil the surface of your painting or gilding later. Air bubbles are introduced by stirring too vigorously, over-heating the mixture or painting the gesso on too thickly.
- Lightly score the face of the board in a criss-cross pattern. Dissolve 1 tsp (5ml) gelatine in 60ml warm water. Use this size mixture to glue the muslin to one side of the board. Smooth out any air bubbles and allow to dry over night. Melt the gelatine mix again (over warm water) and use the remainder to coat the cloth once or twice – this seals the surface and ensures better adhesion of the gesso. When dry, trim off the raw edges of the muslin flush with board edges using a Stanley knife.
- Dissolve 1 tbsp (15 ml) gelatine in 270 ml warm water. Sieve in an equal volume of whiting powder and allow it to sink slowly into the liquid. Stir very gently. The mixture will be lumpy - sieve it into another bowl, pouring gently to avoid air bubbles. Allow the mixture to stand for ten minutes for any air bubbles to rise to the surface - or refrigerate overnight. If necessary, warm the mixture over a pan of hot (not boiling) water and stir gently. It should be the consistency of single cream. If the mixture begins to gel while working, liquefy it over warm water again. Add a little more water if necessary.
- Now shut the door and turn off the 'phone! Your layers of gesso must all be laid on one day or you will find the layers start flaking when you begin to paint. Brush thin layers of gesso mixture over the muslin side of the board, allowing each layer to solidify before applying the next. Apply the mixture with alternate lengthways and widthways strokes. You will be able to apply three or four layers in fairly quick succession. Then have a cup of coffee and let the board dry for half an hour or so before applying a couple more layers. If too many layers are painted on at once, the gesso will crack as it dries. Seven or eight layers in all will probably be sufficient for a flat board, but if you have mouldings to cover or plan to do water gilding you may want to go to thirteen or fourteen layers. Use any leftover gesso mix to coat the unfinished edges of the board if you like. Leftover gesso can be kept in the refrigerator for a few days, but should then be thrown away - as the gelatine 'goes off' it loses its strength as glue.
- Allow the board to dry out naturally (no hairdryers, sunny windowsills or radiators) for several days and then sand smooth. Use the coarsest grade of sandpaper to smooth out ridges and brush marks (a sanding block gives best results) and then polish with the finer grades to an eggshell sheen. The sides of the board are not so important, but bevel the edges and corners to avoid chipping. Use a soft cloth to buff the surface and remove dust.
And for the impatient or lazy, my super-quick board method:
Glue a piece of acid-free white mountboard (get offcuts from the framers) to your piece of ply or MDF: use woodworkers' PVA or hide glue. Weight it down under a pile of heavy books and allow to dry overnight. Trim mountboard flush with the board edges. Paint a size layer onto the card, allow it to dry, and paint with gesso as before - four or five layers will be enough. This will give you a super-flat surface for quick sanding, and is fine for practice pieces and beginners.