Scumbling, a favorite technique of the old masters, is the practice of applying a film of opaque or semiopaque paint in a way that allows underlying colors to peek through. The difference between scumbling and glazing is the opacity?glazes are translucent or transparent. While the distinction is subtle (after all, just about any pigment can be translucent if you paint it thinly enough), the effect is quite different. Scumbling takes advantage of the covering strength of inherently opaque pigments. The underlying colors modify the hue that?s been painted on top of it, rather than the other way around. Many artists begin a painting with a monochromatic underpainting (usually in an umber), upon which they scumble the lighter tonal values, then glaze down the darker areas (see Flesh Comes to Life on page 33). Others work with a grisaillea black-and-white underpaintingtrying to match the tonal values of the scumbled paint to those of the grays beneath it. Either way, the ultimate objective is to blend colors and gray tones by layering one over the other, rather than mixing the pigments together into one single (and possibly muddy) layer of paint.
Some old masters scumbled their landscapes and still lifes with a particular approach. After blocking out the major forms and tonal values in an umber monochrome, they would spread a very thin, even shroud of white paint over the entire surface of the picture. This was called a veil, upon which they would add the remaining colors and details. They?d further use scumbling to soften colors and edges, resulting in a misty or smoky effect known as sfumato.
How to Do It
You can scumble a layer of paint with normal brushstrokes. Or you can scrub the color on, making a circular or semicircular scrubbing-like motion with the brush. This techniquewhich can be rough on brushes, especially when working in watercolor with a sable brush?rubs the paint onto the picture surface. Scrubbing is widely used for scumbling; in fact, many artists regard the two terms as interchangeable.
Scumbling can achieve chromatic effects that are impossible any other way. These effects are particularly valuable to portrait and figure painters who want to capture the vivid but subtle nuances of fleshtones. When used along with glazing, it also creates a fascinating atmospheric effect, in which shadows come to life and colors seem three-dimensional.
The traditional scumbling technique that oil painters favored is rarely used today, having fallen out of favor about 100 years ago. Requiring so much time to produce each painting, it was simply too slow for the impatient artists of the 20th century. Both scumbling and glazing require each layer of paint to dry before the next one can be applied. The old masters dealt with this problem simply by having several paintings in progress at once, working on one while another dried.
Fortunately for contemporary artists, it?s no longer necessary to wait such a long time for successive layers of paint to dry. Mediums such as acrylics, heat-set oils, watercolors and heat-fix watercolors are ready for the next application of paint almost immediately?making the scumbling option much more practical. This may open the door for a welcomed revival of this time-honored technique.
Flesh Comes to Life Relying on mediums that dry much faster than those used centuries ago, I?ve painted a simplified illustration of how the masters used scumbling to develop fleshtones.
2. Switching to heat-set oils, I built up the lighter areas by scumbling in thin layers of opaque fleshtone paint. I used a combination of straight brushstrokes and scrubbing. I took care not to completely obscure the underpainting, except perhaps in the very lightest highlights.
3. I glazed down the darker areas with phthalo blue, a naturally transparent pigment. I also scrubbed barely perceptible amounts of the blue into the halftone areas (to subdue the flesh color); opaque red oxide into parts of the ear; and opaque Genesis yellow into the planes of the ear facing the upper-left corner. These subtle chromatic adjustments create the illusion that the ear is a three-dimensional object within a three-dimensional space.
Butch Krieger, of Port Angeles, Washington, is a contributing editor to The Artist?s Magazine.