Imprimatura is an incredibly simple layer of an oil painting, but it can affect both the process and outcome of an entire artwork. It can be done in different ways, using any color of the artists’ choosing. Maybe that’s why I find it so interesting. A wash of color that is usually hidden under layers of paint reveals much about the artist, his technique, and his vision for the work.
Imprimatura is a term used in painting, meaning an initial stain of color painted on a ground. It provides a painter with a transparent, toned ground, which will allow light falling onto the painting to reflect through the paint layers. The term itself stems from the Italian and literally means “first paint layer”. Its use as an underpainting layer can be dated back to the guilds and workshops during the Middle Ages; however, it comes into standard use by painters during the Renaissance, particularly in Italy.
The imprimatura provides not only an overall tonal optical unity in a painting but is also useful in the initial stages of the work, since it helps the painter establish value relations from dark to light. It is most useful in the classical approach of indirect painting, where the drawing and underpainting are established ahead of time and allowed to dry. The successive layers of color are then applied in transparent glaze or semi-transparent layers.
Imprimatura in Art History
In the Early Flemish Technique of oil painting, as described by Virgil Eliott in Traditional Oil Painting: Advanced Techniques and Concepts from the Renaissance to the Present, an artist would first transfer a carefully-planned drawing onto a primed wood panel, strengthen the lines with ink or paint, and then isolate the drawing under a layer of varnish. Sometimes a transparent toner was added to the varnish, and that toner is what we know as imprimatura. This layer “could be left to dry as an even layer covering the entire panel, or the lighter areas of the design could be wiped out with a rag… while the imprimatura was wet.”
The primary layers described by Elliott are clearly visible in Jan van Eyck’s unfinished Saint Barbara. The meticulous preliminary drawing is submerged in a transparent yellow imprimatura, and subsequent layers of paint begin to define the sky in the background.
We can see Leonardo da Vinci’s use of imprimatura in his unfinished painting, the Adoration of the Magi. The yellowish ground is clear in the background and in the many figures which were never to be fully modelled by the master’s hand.
How to Use Imprimatura in Your Modern Oil Painting
When used in contemporary painting, imprimatura may come in many forms. The artist may choose a warm or cool color base to set the mood of the work. He may also choose a low or high value of the color to set its overall brightness. He may instead decide to omit color completely, and opt for a tonal grey wash.
In the painting course that I attended at Academie Noord in Brasschaat, Belgium, we universally used a yellow ochre for our imprimatura. This served to help combat the yellowing effect that occurs during the aging process of an oil painting, and also to set the midtone for a 3-value wipeout underpainting (the shadows were added with a darker color, the whites were wiped away before the layer dried, and the yellow ochre imprimatura was left to shine through in the areas of midtone). The process we followed is simple:
1. Squeeze the paint onto the palette.
2. Thin the water mixable oil paint with water. We first placed a few drops of water on the palette next to the color, and then mixed it directly into the paint until it reached the desired consistency. If you’re using traditional oil paints, then you would use turpentine or odorless mineral spirits (OMS) to thin the paint.
3. Dip a wide stiff-bristle brush from the hardware store into water or solvent, then squeeze it dry with a rag. Spread the color thinly over the entire painting surface. You can distribute it evenly, in one direction, or even with some spots uncovered. It all depends on the effect you’re going for. The only real restriction is that you apply the color as thinly and flat as possible. You want it thin so that it will dry fast and you can continue on with the painting process as soon as possible. You want it flat so that any bumps or irregularities won’t hamper the following layers.
A word of caution:
While it’s tempting to thin your imprimatura color with turpentine or odorless mineral spirits (OMS) to a near watercolor consistency, it may not be advisable. That is, if you’d like your painting to last. In Traditional Oil Painting: Advanced Techniques and Concepts from the Renaissance to the Present, Virgil Elliott cautions against the use of both solvents and mediums in oil painting.
There is a widespread belief that thinning with solvent makes the paint leaner, and that this is therefore desirable in the early stages of painting. This practice could well cause adhesion problems between layers, as the excessive amounts of solvent normally used in this procedure could weaken or destroy the binding power of the vegetable oil in the paints thus thinned, leaving an underbound layer between the ground and subsequent layers of paint.
He suggests to use the absolute minimum amount of solvents and mediums needed to achieve a desired effect, and whenever possible, to avoid them completely. Using a stiff paintbrush helps to thin out the colors on the painting surface with little to no added medium. If you must thin your imprimatura layer, use only a few scant drops of solvent.