Painting in egg tempera requires a rigid surface.

Traditionally wood has been used, but that is not entirely stable in varying climatic conditions, and good flat sheets are difficult to source. I have always used MDF. It is less likely to bend or warp and is readily available. However, it does need to be prepared for egg tempera use, and the best surface for this is gesso. Not the Acrylic gesso that has now become common. That will not do for egg tempera as it is not absorbent.

The correct gesso surface consists of a glue combined with whiting, a chalky substance. The best and most traditional glue is rabbit skin glue, available from good art suppliers.

The details I give below are for preparing boards with this surface, the best for egg tempera. Explanations about how to make egg tempera and some of the medium’s techniques can be found in my articles published in the January and February editions of the Leisure Painter available in the shops from November and December respectively.

Materials you will need:

• Rabbit skin glue. This is sold in granules or already mixed, as in the first picture above. I have used both forms, but the glue already mixed and ready use is easier. I bought this pot by mail order from Cornelissens in London.
• Whiting. This is a chalky ingredient and the main constituent, with the glue, of true gesso necessary for egg tempera. The more recently invented Acrylic gesso is not suitable for egg tempera as it is not sufficiently absorbent for this medium.
• Titanium White, in powder form. A small amount of this added to the mix will make the gesso that bit whiter and more brilliant, creating more luminous colours in the final result. But not more than 10% of pigment should be added or the gesso will not be strong enough. I used just 10% in my mix. I purchased both the whiting and the Titanium white online from Cornelissens, but other stockists could supply these.
• Some sheets of MDF board. I find MDF the best for my egg tempera work. These boards provides a sound surface when properly sized and gessoe’d. I still have boards I made over thirty years ago that are in perfect condition. I prepared three boards for this demonstration, each half an inch thick. Two were size 30 x 42 cm and one size 42 x 60 cm. I had them pre-cut and delivered, but you can clearly cut your own sizes to suit.
• A double boiler or steamer. I used a steamer (used for steaming food) but if you don’t have that or a double boiler just resting a bowl in a saucepan would do. The important thing, when melting the glue or keeping the mixed gesso warm, is not to ever let it boil as I understands that weakens the glue.
• Sandpaper. You will need different grades, a medium grade to sand and give slight tooth to the MDF before sizing it, and a fine grain (about 600 grade) to gently sand the final coat of gesso, or between coats if you wish.
• A bowl for mixing the gesso. I used a glass one as it was the right size for my steamer and easy to clean (which should be done immediately after you’ve finished using before it sets hard).
• House painting brushes. For applying the sizing and the liquid gesso to the MDF.
• A set of weighing scales. These are needed to weigh the quantities of glue and whiting before mixing.

Preparation of your board:

Lightly sand the surface of your board with medium grade sandpaper, front and back, then wipe away the dust with a cloth or kitchen paper.

Spoon a small amount of the rabbit skin glue (a jelly-like substance) into a bowl that can tolerate being heated on the steamer. Add a little water to the glue. It should be three parts glue to one part water.

Dissolve the glue in your bowl on top of the steamer, with the water simmering gently below.

When the glue has completed dissolved remove it from on top of the steamer. Be careful not to burn your hands on the steam still rising as you do this. The bowl will also be hot so should be placed on a mat next to your board. Then paint your board or boards whist the glue is still warm and liquid, painting the front, back and as well as along the edges thoroughly but carefully leaving a smooth surface.

MDF panel sized and drying.

Making the gesso and coating the panel

First you need to measure the quantities of ready solution of glue and whiting/Titanium white mix. They need to be equal quantities by weight. For my three panels, two 30 x 42 cm and one 42 x 60 cm, I measured out 500 grams of the glue and 450 grams of the whiting together with 50 grams of Titanium white. For my three pieces of MDF this quantity enabled me to paint six coats on the fronts and three on the backs. A minimum of six thin coats is needed and up to ten.

When you have decided on the correct quantity dissolve the glue in a bowl on your double boiler or steamer, or just by resting the bowl in the top of a narrower saucepan, as long as it heats without boiling.

Then slowly sieve in the whiting/Titanium white mix, to eliminate any small lumps, and stirring gently as you do this.

When all the whiting mix has been added continue to stir the liquid gesso gently for a while, maintaining its warm temperature, tapping it occasionally to try an reduce the number of air bubbles, perhaps breaking a few on the surface as they come up. This is now ready to use.

The first layer should be applied with a scumbling motion to eliminate the chances of air bubbles or pin holes. this can be done with the brush, or even more smoothly with the hand (as below).

However, this has to be done quite quickly for this thin layer of gesso dries rapidly and then becomes just sticky and difficult to smooth. If in doubt just use the brush.

The second and subsequent layers need to be painted on in smooth parallel strokes, not going over the area just painted, and firm enough to eliminate any air bubbles along the way. Each layer needs to be applied when the preceding one is touch dry, but not left to dry for any length otherwise the next layer will not adhere properly. Some artists suggest a light sanding with fine sandpaper (e.g.600 grade) between layers, and damping the preceding layer. I only sanded the second to final layer before the finishing sand. And I found that each layer being just touch dry didn’t need me to damp it down before applying the next layer.

This shows a board with just a few layers of gesso put on. Brush marks can still be seen. Thin layers should be painted on, each going at right angles to the last layer. The backs and side of panels also need to be painted but the backs need only be given several coats. The back can be done the next day but should not be left longer than that after the front is painted. Spare gesso can be kept in the fridge overnight, but not for longer, and the skin will need to be fully broken up again when it is re-heated. A minimum of six layers, and up to ten, should be applied to the fronts of tha panels, the surface you will use for your egg tempera painting, and make sure you write down the number of each coat as you put it on. It is easy to lose track of how many you’ve done! Applying my layers took several hours. A good section of the day needs to be set aside for the whole process, including cleaning up afterwards.

The gesso mixture will cool a bit each time you’ve finished giving a coat to your panels. When it does cool a slight skin forms on top. The dish containing the mixture needs to be returned to the heat, where the skin is easily broken down as it warms through properly again before painting the next coat. I kept the water in my lower saucepan simmering or warm throughout the process of doing all my layers, turning the heat back up periodically to heat the mixture through again more thoroughly. The picture above shows the mixture after I had used it for a number of coats.

After adding the final coat of gesso give it a light sand over the surface, using 600 grade sandpaper. I used wet and dry and did wet it to smooth out a couple of bumps, but be careful to use this lightly.

Then to get the surface really smooth use a damp cloth and go over it with gentle circular motions.

Finally when it is dry, you can buff it with a clean dry cloth to raise a sheen. The panels should then be left for a few days before a painting is begun on them. The gessoe’d boards can be kept for many years before painting if wished, but they should be stored flat.

Cleaning up: Brushes and spoons etc can be cleaned with warm soapy water if not left to dry for too long. likewise with any splashes that may have reached cooker or floor! Any remaining mixture left in your bowel should, as much as possible, be scooped out and put in the bin. If you try and flush it down the sink it will begin to clog your pipes! Finally, good luck with your painting!