Drawing with a silverpoint, or more correctly a metalpoint (a stylus made of silver, lead, gold, tin or other metal and alloys) requires a hard and abrasive ground to draw on. Tiny metal particles will detach from the stylus and deposit on the ground leaving a visible mark.
Preparing the ground for Silverpoint Drawing
Materials & Tools
Rag paper commonly available in the 15th century Europe was too soft to be used for silverpoint drawing as is, and required an additional treatment: application of a coating typically containing bone white (calcinated bone powder also called bone ash) with additions of colored pigments and/or chalk.
The binding medium used to attach bone ash and pigment particles to the surface of the paper was typically rabbit skin glue.
This preparatory process is extensively detailed in the treaties of the era and has been corroborated by subsequent scientific examinations of old master drawings from both Northern and Southern Europe.
WHAT KIND OF BONE IS GOOD FOR TREATING THE PANELS. CHAPTER VIIThe craftsman’s handbook by Cennini, Cennino, active 15th century; translated by Thompson, Daniel Varney, 1902- ed
You must know what bone is good. Take bone from the second joints and wings of fowls, or of a capon; and the older they are the better. Just as you find them under the dining-table, put them into the fire; and when you see that they have turned whiter than ashes, draw them out, and grind them well on the porphyry; and use it as I say above.
CHAPTER V. HOW YOU BEGIN DRAWING ON A LITTLE PANEL; AND THE SYSTEM FOR IT.
And when this little panel is thoroughly dry, take enough bone, ground diligently for two hours, to serve the purpose; and the finer it is, the better. Scrape it up afterward, take it and keep it wrapped up in a paper, dry. And when you need some for priming this little panel, take less than half a bean of this bone, or even less. And stir this bone up with saliva. Spread it all over the little panel with your fingers; and, before it gets dry, hold the little panel in your left hand, and tap over the panel with the finger tip of your right hand until you see that it is quite dry. And it will get coated with bone as evenly in one place as in another.The craftsman’s handbook by Cennini, Cennino, active 15th century; translated by Thompson, Daniel Varney, 1902- ed
Take the bones of the thigh or wings of capons, or chickens, and also those from the thighs and shoulders of capons are good, and put them in the fire, leaving them there until they become white; then take them out and grind them finely on a porphyry stone, and preserve this powder.
Then take a tablet of boxwood or fig wood, cleaned well with sepia, the kind used by goldsmiths for imprinting, and put some of the bone powder on it at your discretion, mixing it with saliva, and spread it carefully all over, and patting it with the palm of your hand until it dries.
Once it is dry, you can draw on it with a stylus of silver, or any other that has silver points; and if one would like to draw on sheepskin or parchment, the same stylus can be used, first applying a little bone powder on the paper, like varnish.
And if you wish to clarify the drawing, you can lightly touch the outlines with ink, applied with a fine-pointed tempered pen, and then shade with a watercolor brush, by mixing two drops of ink in as much water as would fit in a walnut shell.
It is also possible to draw on paper without bone powder using a stylus made of lead, which is made of two parts lead and one part tin, well beaten with a hammer. And when you wish to remove any imperfectly made marks, rub them with a little bread pulp.Il riposo di Raffaello Borghini, 1584
Poi abbiassi la tavola o di bossolo, o di fico ben pulita con seppia di quella che adoperano gli orefici per improntare, e vi si metta sopra della polvere dell’ossa a discrezione impastandola con lo sputo, e distendendola per tutto con diligenza, e battendo con la palma della mano avanti si asciughi, e come è secca si può disegnarvi sopra con stiletto d’ariento, o d’altro pur che abbia le punte d’ariento: e chi volesse disegnare in carta pecorina, o bambagina si può col medesimo stile, dando prima un poco di polvere d’ossa sopra le carte a modo di vernice;
E volendo chiarire il disegno, si potranno leggermente toccare i dintorni con inchiostro, dato con penna temperata sottile, e poscia con pennello di vaio adombrare con acquerello, che si fa mettendo due gocce d’inchiostro in tanta acqua, quanto sarebbe in un guscio di noce.
Ancora si può disegnare sopra le carte senza la polvere dell’ossa con lo stile di piombo, che si fa di due parti di piombo, e una di stagno benissimo battuto col martello, e quando si volesse levare qualche segno non ben fatto, freghisi sopra con un poco di midolla di pane.
The above citations from Cennino Cennini and Raffaello Borghini suggest that this treatment was also used to prepare wooden panels and other supports for drawing with a metalpoint.
In Cennino’s times paper was not yet readily available and accessible for everyone (as it was about a half century after, in Leonardo’s times) thus there was a need to exercise drawing on the same support, covering it with a fresh ground each time to start a new drawing.
Not only Italian artists made silverpoint drawings. This technique was widely used by Northern Renaissance artists, such as Jan van Eyck, Rogier van der Weyden and Albrecht Dürer to name a few.
Materials used for drawing were similar on both sides of the Alps. Scientific analysis of the above drawing shows that silver and gold points were used on a paper prepared with bone white.
See: A metal-point drawing by Jan van Eyck? Notes on the Material Aspects by Birgit Reissland and Luc Megens
Let’s do some Alchemy!
Ingredients to make the silverpoint ground:
Animal skin glue, tipically rabbit glue was and is very widely used in painting, violin making, production of illuminated manuscripts, restoration of all the above and more.
Oak galls can be found on oak trees all around the globe. In late winter and early spring, they are easier to identify while an oak tree is leafless.
Numerous plants, such as hawthorn tree, contain tannins in various parts of the plant.
White lead (lead carbonate), artificially produced since the times of ancient Greeks and probably even earlier, or its mineral near equivalent cerussite were until quite recently very commonly used in painting of any kind and medium, all branches of industry and even cosmetics.
Unfortunately, the toxicity of this pigment has led to severe trade and production restrictions and this pigment is now largely replaced by zinc an titanium whites.
Clean water, typically rain or spring water was used. We will use distilled water.
- Colored pigments: green or red earth, ochre, azurite and other pigments were used
- Chalk: [calcium carbonate], also known as Bianco di Spagna, sometimes simply called crea o creta in the treaties. Used to give more body to the ground
- Lead-white: to make a more covering white ground, and/ or to compensate the bone white (that tends to gray)
- Paper: it is advisable to use pure cotton soft and heavy paper (300+ gsm)
Metalpoint ground recipe:
- Paper: rag or 100% cotton paper would be ideal and historically accurate, but any paper thick enough will do.
- Size: 40 gr rabbit glue X 1000 ml of distilled water. The proportions may very depending on the glue, the general idea is that you don’t want this size to be too strong.
- The filling: 1×1 proportion of glue and bone white (or bone white with addition of pigments)
Step 1: Prepare the paper
You should stretch big sheets of paper, smaller pieces can be used without stretching.
Step 2: Prepare the size
Rabbit skin glue should be soaked in water overnight prior to being used. When ready, heat the soaked glue in a double boiler (Bain-Marie).
Step 3: Prepare the ground
Take equal amounts of bone white and hot glue, put them on a slab or other clean and hard surface, grind the paste with a muller or pallet knife as thin and smooth as you can.
Step 4: apply the ground
Apply enough coats of this mixture of size (and pigment if you want it colored) to your pieces of paper to produce an agreeably even tone. A wide flat bristle brush is best to use for this.
Let each coat dry thoroughly before you put on the next. To get a very smooth and uniform surface, you can apply the ground in a crossing direction in respect to the previous layer. Try not to insist too much with your brush when applying the ground.
If the papers tend to curl badly in drying or the surface of the paper becomes to hard and shiny, add a little water to your size.
Hints from the Masters
Materials & Tools
Bone Ash + White
A standard preparation for metalpoint drawing all around Renaissance Europe was plain bone white pigment bound with a week size, colla dolce, a sweet glue, as Leonardo would call it: probably a week solution of hide glue or gum arabic.
Bone white is actually light gray in tone, therefore sometimes lead white would be added to make the preparation lighter.
An exclusion from this rule might be Hans Holbein the Younger who used silverpoint as a suplementary mediun in some of his drawings, where the paper was prepared with chalk (calcium carbonate).
For blue grounds like the one in the example above, Leonardo used bone white and indigo pigments.
To achive pink or violet paper tone, Leonardo would use the carmine lake, a pigment made of a deye derived from the cochineale insect settled on alum.