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.
296. To prepare parchment, or paper, primed panels, and linen, so that you may be able to draw upon them in black, with a pencil or stile of gold, silver, bronze, or brass, as is done upon panels of boxwood whitened or covered with bone or stag’s-horn burnt and whitened in the fire.
Take bones of any animal or bird, or stag’s-horn, which is better, and burn it, and make it white and friable and soft by long and violent boiling, and afterwards grind it upon a hard stone with pure water. Then put it on a brick of baked clay or of white chalk, that the moisture may enter into it, and that the bone may remain thickened and almost dry. Remove it from the stone, and burn it a second time in a charcoal fire, and make it perfectly white and fine in a crucible in which silver or gold is usually melted, and afterwards, that it may be made still more fine and white, grind it a second time upon a stone with water, in the same way as you did before; and then if you wish to use It immediately, wet up as much of it as you require in a shell or a glazed earthen jar, with size made from glue or from clippings of white leather or parchment, and which must be of a moderate consistence and warmth.
Having done this as directed, paint or draw with it, with a broad paint-brush, upon paper which has been polished with a boar’s tooth. Also lay it over parchment, cloth, sindone, and wooden panels, and permit it to dry. And then, if the first coat is not sufficient for it (which may be known by drawing on it with a stile of brass, or bronze, or copper, or still better of silver, and seeing whether it makes black marks or not), you must give it another coat of the said bone-dust, keeping it warm in the vase in which it stands over a slow fire, particularly in winter, lest it should be congealed by the cold, on account of the glue with which it is mixed, which hardens with cold; afterwards let it dry, and try it again by drawing upon it with a stile as before. And so you must apply this bone or horn as many times as you see necessary, though it is true that the second coat usually suffices, and frequently the first.
And note, that if you wish the paper, after it is thus painted, to be very smooth and polished and without any inequalities or roughnesses, that it may be better to draw upon, you must polish and burnish it, holding it under another paper not painted on, upon which you must rub a boar’s tooth, or a hard and polished stone, or any other instrument fit for burnishing. And know, that if you wish to make this preparation of various colours, it is necessary, while grinding the horn or bone upon the said stone, and wetting it in a shell or a glazed earthen vessel, when you wish to paint the paper, that you should mix with the horn or bone whatever colours you wish, separately, which must however be ground very fine upon the said stone with pure water.
Afterwards, if any of the said horn remain, whether white or coloured, it can be preserved, because, although what remains becomes dry by keeping, it may still be of use to lay upon other paper, like any other colours, by being wetted up with pure water, not sized; because, although the water of the first wetting dries up, yet the glue of the first wetting still remains there, and in sufficient quantity; for in the exhalation and evaporation of the moisture of the first wetting, the strength or substance of the glue is not exhaled or evaporated, but only the water.
And if any of the first quantity of bone or horn, not mixed with any colour or glue, remains in the vase, shell, or saucer, you may put it on a lump of chalk, or on a brick of baked clay, that the water which is contained in it may be dried up, and may be exposed to the air or the sun, that it may dry completely; and afterwards, when you wish to use it, you must temper it with size as originally directed, as there is not any size or glue mixed with it. You can also colour it with various colours, mixing them with it, as before, according to your taste, as above mentioned. And note, that if you have no stag’s-horn, the bones of the stag are good, as also those of any other animal or bird, as has been already mentioned.
De Coloribus Diversis by Alcherius in Manuscripts of Jean Le Bègue, 1368–1457, Mary P. Merrifield, Medieval and Renaissance treatises on the arts of painting : original texts with English translations
WHAT KIND OF BONE IS GOOD FOR TREATING THE PANELS. CHAPTER VII
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.
CHAPTER XV. CHOW THE GREEN TINT IS MADE ON PAPER FOR DRAWING; AND THE WAY TO TEMPER IT.
[…] When it [the bone ground] is dry and done, take a penknife, and rub lightly over the tinted sheet with the blade, so as to remove any little roughness that there may be on it.
CHAPTER XVII. HOW YOU SHOULD TINT KID PARCHMENT, AND BY WHICH METHOD YOU SHOULD BURNISH IT.
[…]If it should come about that the paper or parchment is not smooth enough to suit you, take this paper, and lay it on a walnut board, or on a flat, smooth slab; then put a sheet of good clean paper over the one which you have tinted; and, with the stone for burnishing and working gold, burnish with considerable strength of hand; and so, in this way, it will get soft and smooth. It is true that some people like very much
The craftsman’s handbook by Cennini, Cennino, active 15th century; translated by Thompson, Daniel Varney, 1902- ed
to burnish directly on the tinted paper, that is, to have the burnishing stone touch it and penetrate it, so that it acquires a little polish. You may do as you please, but that first method of mine is better. The
reason is this : that rubbing the burnishing stone over the tint offsets, by reason of its polish, the polish of the style when you draw; and furthermore the washes which you put on with your ink do not look
so well blended and clear on this as in the method first described. But, nevertheless, do as you please.
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
Original textPoi 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 Alcherius, 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:
GLUTINUM
Hide glue, in case of drawing and painting grounds, typically a rabbit skin glue was and is very widely used in painting, violin making, production of illuminated manuscripts, restoration of all the above and more.
CINIS
Bone Ash, or Bone White pigment is produced by calcinating dried bones of chickens, capons and bigger animals. The heating at a very high temperature with access of oxygen turns the bones to calcium phosphate, a white, very hard and durable material. Bone white was used almost exclusively for metalpoint drawing.
AQUA
Clean water, typically rain or spring water was used. We will use distilled water.
Additional ingredients:
- 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:
Ingredients:
- Paper: rag or 100% cotton paper would be ideal and historically accurate, but any paper thick enough will do.
- Size: 40 gr rabbit skin 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.
Step 5: Burnish the Paper
As both Alcherius and Cennini note, if a smooth finish is desired, it is best to burnish the prepared paper. In the Middle Ages this was done primarily with animal teeth, whereas today an agate burnisher, commonly used by modern gilders, serves the same purpose. To protect both the colored paper and the burnisher, place a clean sheet of paper as a buffer between the stone and the silverpoint ground.
Coloring hints from the Masters
Materials & Tools
Pure bone white pigment mixed with a binder produces a very light gray ground. Throughout the Renaissance, artists often added colored pigments to this mixture to create a more visually interesting effect and, at the same time, to allow the use of white highlights in combination with the metalpoint stylus within the chiaroscuro technique. Unlike ink-and-white chiaroscuro drawings, where papers could be prepared with rich, deep tones, silverpoint grounds had to remain on the lighter side of the tonal scale. Otherwise, the silverpoint marks would blend with the ground or even appear lighter than the paper itself.
Cennini mentions the following color combinations for paper grounds in his treatise:
- Green paper: green earth, cinnabar, yellow ochre, lead white (Chapter XVI)
- Violet paper: lead white and hematite (Chapter XVIII)
- Indigo paper: indigo and lead white (Chapter XIX)
- Pink paper: red earth, green earth, and lead white (Chapter XX)
- Flesh tone paper: cinnabar and lead white (Chapter XXI)
- Grey paper: lead white, probably lamp black and red earth (Chapter XXII)
- Inert charge for metalpoint drawing: bone white
Here are some examples of colored grounds used by the great masters:
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, and has a week tinting power, therefore often 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).
INDIGO
Leonardo’s blue and blue-gray metalpoint papers were prepared with grounds containing a mixture of bone white, indigo and small quantities of additional pigments, typically ochres and other earth colors, but sometimes also lead white, carbon black and vermilion.
Source: [Italian] Le tecniche del disegno tra Leonardo e i leonardeschi. Un approccio scientifico, 2019, Gianluca Poldi
KERMES
To achieve pink or violet paper tone, Leonardo would use a bit of indigo mixes with the carmine lake, a pigment made of a dye derived from the cochineal insect (kermes vermilio) settled on alum.