Rubens Technique 

In the process of copying the Two Satyrs by Peter Paul Rubens, I tried, within the limits of my abilities, to guess the sequence of the layers and the opaque or transparent nature of the colors of the original painting. The outcome is this article, which provides a complete step-by-step demonstration of the underpainting technique used by painters for almost four centuries.

Understanding the glazing technique is the key that allows you to “read” almost any antique painting.

Reference original painting:

“Two Satyrs” by Peter Paul Rubens
(Oil on wood board 76 x 66 cm Alte Pinakothek – Munchen)

Dimensions:
80 x 60 cm (31,5″ x 23,6″)

Grid copy

I transferred the drawing on the board from the sheet of paper on which I made the copy in a grid, using the “carbon paper” method: the back of the sheet is uniformly spread with graphite; then, the sheet is placed on the board, and the drawing is traced with a pen or a hard lead pencil. The graphite on the back of the sheet is fixed on the painting surface in the same way that common copy-carbon paper works.

Ink drawing

With brown china ink diluted with water, I went over the drawing. Then, I faded it further by sanding it with very fine sandpaper (P1000) mounted on a pad. Brown ink is better than black ink because it integrates with earth colors, while black ink would be difficult to cover. You can use a metal nib, but on a smooth, hard surface it is better to use a good round brush or a brush-pen with a tank.

Imprimitura

When you make a drawing on a white surface, you can add only shadows; you can’t add lights because white on white doesn’t create any contrast. Drawing on a toned paper allows you to add both shadows and lights.

In the underpainting technique, you paint on a toned surface so you can add dark tones and light tones, using the undertone as mid-tone.

I used a mixture of yellow ocher, red ocher, bitumen, Cassel earth, and burnt umber very diluted with Liquin and oil essence. Beyond the colors used, which give a very relative indication, in this case, I wanted the tonal value to be the same base tone as the satyr in the background.

Underpainting

The umbra layer is a monochromatic completed version of the painting. The goal is to map the tonal range and value. The paint has to be thick in the dark areas and thin or diluted in the light areas. You should use just one earth color to create a series of more or less diluted tones.

Traditionally, earth colors like burnt umber were used as an underpainting for several reasons: it’s a cheap pigment, it’s chemically stable, and it dries quickly.

I used burnt umbra, burnt Siena, bitumen, and Cassel earth, but just one earth color would have been sufficient. In the image below, the tonal study is completed and painted.

Grisaille

The dead layer is the color’s underpainting; its function is to reflect lights. The lighter areas will be white, the mid-tones will be grey, and the shadows could be from the umbra layer or painted with a darker mixture of black and white. Actually, there’s no rules about grisaille tonal range. You can cover the entire surface with grey tones or apply just white in the lighter areas, leaving the umbra layer for mid-tones and shadows.

I started by adding a rather diluted shade of gray (from slides 14 to 16 in the video) just to create the areas of fusion with the shadows. Then, I spread a uniform tone of light gray on the whole figure of the satyr in the foreground (slides 17 to 20 in the video). To complete the grisaille, I added the areas in maximum light with pure white (slides 21 and 22), and once dry, I painted with the usual mixture of Liquin and petroleum spirit.

The lion fur and the hat of the satyr in the background were painted with thicker brushstrokes, mainly with natural Sienna, yellow ocher, and dark Naples yellow.

Colors layer (Glazing)

The colors layer goes over the grisaille. It has to be transparent so that the light can be reflected by the dead layer.

Try to imagine red-colored glass: when you look at a light source through it, you see beautiful and saturated colors; instead, if you look at it in the palm of your hand, the color is darker. This is because a transparent material like glass doesn’t reflect lights. Transparent layers like glass need an underpainting that reflects lights through them so they appear saturated and vibrant.

In the past, colors like ultramarine blue were very expensive, but even a vermilion wasn’t cheap, so painters didn’t want to waste these colors, and glazing allows for the best results with small amounts of paint.

The first glaze (image 23) was made with asphaltum/bitumen (Rembrandt Talens series), followed by a mixture of yellow ocher, clear vermilion, and silver-white. Then, I continued to add glazes, increasing the yellow ocher and the vermilion, sometimes stretching them pure where it was needed. On the bottom, above the figure of the satyr in the background, I applied a glaze of indigo. I made the crown leaves and grapes with mixtures of titanium white, light Naples yellow, and bladder green.

Details:

Review some shadows, add the highlights with pure titanium white. Three coats of varnish: Liquin and petroleum spirit at 50%.

The wood board

The preparation of the board involved several phases. I followed Cennino Cennini’s instructions, but I adapted them to the materials I had, trying to obtain a support similar to that of the original.

Sizing (Apprettatura):

A panel or a wooden board must be properly prepared before painting on it.

Wood is very sensitive to moisture and tends to bend if one side is more or less moist than the other. To reduce the tendency of the wood to expand and shrink, spread some coats of rabbit glue on both sides and close the pores of the wood to make it impermeable to humidity. Then, apply a broad-weave canvas (tela pattina) with glue to facilitate the grip of the mestica.

The canvas, in addition to accommodating the mestica, allows for greater resistance to any movement of the board, reducing the possibility that the painting surface will split or crack due to expansion or shrinkage of the underlying wood.

Materials:

– Wooden board or similar material panel (hardboard, mdf, etc.)

– Rabbit glue

– Linen or jute canvas flap canvas, 20 cm higher and wider than the panel.

Make a diluted glue (I used a proportion of 1 part rabbit glue to 15 parts water), put it in a bain-marie, and divide in half. Add 1/3 of water to one half, bring to a boil, and spread a generous coat of this glue on both sides and on the edges of the panel. Since the water has diluted the glue, it will penetrate deeply into the wood.

Once the first coat is dry, use the rest of the glue (not boiled), apply two more coats over the entire table and soak the canvas that will receive the mixture. Spread and stretch the glue-soaked canvas on the wood board by gluing the excess edges to the back of the panel. Let it dry for two days.

Now it’s time to apply the gesso (mestica):

Materials:

– Fine gesso (white chalk)

– Water

– Rabbit glue

To ensure that the gesso is well mixed with the glue, you should temper it first with water to make it more soluble. Remove the excess water by pressing the dough into a rag. Make the glue by dissolving one part glue in eight parts water; once the glue has swollen, taking up the entire volume of the water, place it in a water bath.

Once the glue is smooth, add the plaster, continuing to mix until a homogeneous and not too thick cream is obtained. Spread the first coat of this gesso, trying to make it penetrate into the texture of the canvas as much as possible. Once dry, shave the surface with a spatula.

Continue to overlap several layers of gesso by reversing the direction of the brush strokes so that each hand moves perpendicularly to the previous one, without waiting for the plaster to dry completely between one hand and the other.

When the weft of the canvas is no longer visible, leave it in a horizontal position on a table to dry for two days.

Board finishing:

Once dry, smooth the surface first with coarse and then with fine sandpaper (I recommend using a pad for this operation; otherwise, you could get an uneven surface). After that, the gesso should be smooth and very absorbent; the oil of the colors will be absorbed by the plaster migrating toward the bottom, leaving the pigments free of binder. For this reason, you should make the gesso less absorbent by applying a coat of glue, varnish, or oil.

Before isolating the mestica, you must be very careful not to smear the plaster surface with sweat from your hands or with fatty substances that would prevent good color adhesion, as the gesso will absorb them so deeply that you will have to start over from the beginning. To isolate the gesso, I spread both a coat of glue and a coat of Liquin diluted to 80% with oil essence.

Once dry, the board is ready. Use some bitumen diluted in essence of turpentine on the back and on the edges of the table to protect it and further waterproof it. Now, hang the board, possibly tilting it slightly toward the floor so that dust cannot deposit on the surface of the picture.

Notes:

The preparation of my board took about a month (between tests, waiting times, and purchase of materials). I could probably do it faster, but the preparation of the wood board is still a long and complex process.

Also, I spent about a month painting it, plus another week for the final varnishing.

Books about Rubens technique and underpainting technique in general:

“Oil painting” by Charles Lock Eastlake

“La tecnica della pittura dai tempi preistorici ad oggi” by Leone Augusto Rosa (1937 Ediz. : Società Editrice Libraria )

“The history and techniques of the great Masters – Rubens” by Andrew Morrall (Ed .: Vallardi I.G.)

Author: Giovanni Lucifero