description of Peter Murphy's technique
On this page Peter takes us through, step by step, the process used to paint an angel using the method described by Cennino D'Andrea Cennini, in his famous 15th century treatise on painting techniques, 'Il Libro Dell Arte'Preparing the panel
The preparation of the panel is crucial, It's difficult to find timber that does not warp or split, so I use good quality plywood for my panels. These can be ornamented with moulding to create complex gothic-style panels. I cover the surface, including any framing or moulding, with cloth such as unbleached cotton or sheets. These are stuck in place using hot gelatine glue (one sachet of gelatine to half a pint of boiling water), taking care that the cloth dries perfectly flat to the panel without any air pockets. The cloth should overlap all edges. When this is dry the next day. I trim all the edges with a very sharp craft knife.
Gesso
Gesso is a powder, gilders whiting, mixed with a suitable glue, such as rabbit skin or gelatine. I find gelatine easier to use (one sachet of gelatine to twelve times its volume of boiling water).
Keeping the glue warm, stir in whiting until you have a smooth creamy paint. This is applied warm using a simple decorating brush. I recommend between eight to twelve coats, applied at 20 minute intervals on the same day. Leave the gesso to dry for a couple of days before smoothing it down with a scraping tool or abrasive paper. Always finish with the finest abrasive paper available and a cloth, to give it a perfect ivory- like finish.
Drawing and incising
I keep the drawing simple and light, as heavy graphite marks can be seen through the dry tempera. I make a clear line drawing in HB pencil, with no shading. The lines are then lightly incised into the panel using a stylus. I often prepare a drawing to scale on paper and then transfer it onto the panel by rubbing the reverse with red/brown chalk, then going over the lines with a HB pencil.
Any lines to be seen under the gilding - such as the rays radiating from a halo - are now incised into the panel using a fine pointed stylus. Halo lines should also be added at this point using dividers.
Applying bole
A special red clay, gilder's bole, must be painted on to surfaces to be gilded. This provides a cushion for the gold and when it is burnished, the warm colour of the bole stops the gold from appearing greenish in hue.
Bole is mixed with a diluted solution of gelatine and water. The first coats are transparent and a solid red/brown layer is built up gradually.
When the bole is dry it should be rubbed down with a cloth, until it changes from a flat red brick colour to the colour and finish of polished mahogany.
It must be perfectly smooth and free of any grit.
Gilding
I set up the panel so it's inclined slightly towards me, then cut a piece of gold leaf of the desired size. I use distilled water with a tiny amount of very weak gelatine solution and a few drops of meths to wet the area to be gilded. A good watercolour brush or a gilder's mop can be used. The wet area should be slightly larger than the gold. I rub the gilder's tip against my face to pick up a little moisture/static and use it to pick up the gold leaf, placing it face down on to the wet bole and leaving it to dry.
Tamping down the leaf
This procedure is repeated all over the panel, slightly overlapping each piece of gold and tamping - or pressing - it down with cotton wool after every three leaves or so, until the area to be gilded is covered with leaf.
Burnishing
The gold is allowed to dry for an hour or less, depending on the weather, and then burnished.
Gently rubbing on the gold with an agate burnisher produces a shine and the crumpled, dull gold begins to take on a mirror finish. I gradually increase the pressure and carefully move around the panel in the order I put on the leaf. Any areas where the gold has not taken will . now become obvious and can be patched with small pieces of gold leaf.
Stamping
After the gold is burnished, it can have any stamped decoration applied.
Small, round punches are good for making lines of stamped circles around the outer edge of haloes and can even be used in clusters to make decorative motifs such as flowers or crosses. For more complex patterns and designs, special punches have to be made or obtained.
Mixing pigment
I paint with dry pigments, mixing them into paint with egg yolk as needed. Some need to be ground with water but most simply mix into paint using a mixture of egg yolk and water with a drop of wine. The yolk can also be mixed 50:50 with flat beer. Alcohol seems to help the consistency of the paint.
Painting the robes
For the robes of the angel I mix three different values of a purplish red: dark, medium and light. I start with the darkest areas, such as the shadows in the folds then the mid tones and the highlights. Working quickly with fine shorthaired brushes, the three values of the colour are blended together to achieve a subtle modelling of the folds. I use a slightly darker version of the same colour for the shadows and highlights are added with the lightest colour mixed with white. For very subtle touches, a fine longhaired rigger can be used.
Wings
The wings are modelled in a similar way to the robes but much more obvious steps are left between the colours, and there is no attempt to blend.
This gives a more dramatic effect and is best achieved by mixing up and down from a mid tone, going gradually lighter in one direction and darker in the other.
Head
First the hair is modelled by blocking in the whole shape with a mid red/brown colour. The outlines of the hair and shadows are then applied using a rigger, and the same colour is darkened.
Then the blocking colour, mixed with some yellow ochre and white. is used to model the waves and curls.
Finally, some almost-white highlights are sparingly applied and bring the hair to life.
Face
The face and hand are blocked. in with a cool, pale olive green (yellow ochre and chrome oxide) and the shadows and features are carefully painted in with a mixture of yellow ochre and brown. This layer is subtle and acts as a guide to the next layers of highlighting
Flesh
The warm flesh colours are applied using a mixture of yellow ochre, cadmium red and titanium white that gradually becomes lighter as I add more and more white to the mixture. After blending and modelling back and forth, as with the robes, some almost-white points can be added to places like the tip of the nose and the arch of the brow.
It is important to remember that the cooler olive green underpainting can be left to show through to indicate shadows.
Touches such as the lips and eyes can now be added. Black is only used for the top line and pupil of the eye and the centreline of the mouth. A pinky red 'apple' can be carefully hatched on the cheek using the finest of riggers barely loaded with pigment.
Detailed gilding
Finishing touches can be applied to your tempera painting after allowing it to dry for a few days. Gold leaf that comes on transfer paper can be used to make gilded patterns on the robes. I carefully apply water-based acrylic size mixed with a little water and some yellow pigment to wherever the gold is to stick. This size is used to paint lines and patterns on the robes with a very fine rigger brush.
Final touches
After a few minutes the size is tacky but no longer wet, and the transfer gold leaf can be pressed on to it. With luck when I peel the paper away. the gold will have stuck exactly where the size was applied and not anywhere else.The ragged edges of the gold are cleaned up with a soft brush and the panel painting is complete.