Handout no. 2: glazing & scumbling over the dried underpainting
In oil painting, the simplest form of a glaze is a mixture of transparent paint plus a medium containing oil. Glazes are spread over the top of opaque paint that has been allowed to dry. Light travels through the glaze and is reflected back off of the opaque layer below. This creates a glowing effect similar to looking at a brightly lit white wall behind a film of colored cellophane.
Glazes are applied with bristle brushes on canvas with medium to coarse weaves, and with softer brushes on smooth panels and portrait linen. The objective is to work the paint into the weave of the canvas and into the low points of any thick brustrokes created in the underpainting stage. Any irregularities in applying the glaze may be tapped out with a soft large brush--such as a fan blender, large mop brush, or even a makeup or shaving brush.
The consistency of a glaze should be like cooking oil or slightly thicker. It should first be applied to areas that need the most intense color and spread out to areas that need less, making use of the remaining paint in the brush. The surface should be moist when the glaze has been smoothed over the underpainting--not runny or slick. If the color is too intense, it may be removed by wiping the brush on the rag and continuing to work the paint, or by directly wiping away paint with the clean rag. Highlights that have been glazed over may be revealed by wiping with a rag lightly moistened with medium.
Details in the glazed areas are most easily painted using a mixture of the glaze colors--or any transparent colors that give you the color you want--but without any medium added. Painting this mixture into the glaze will blend the two paints so the leaner mixture (leaner meaning no medium added) will get some of the drying benefit of the Liquin that is part of the medium. Most transparent paints are fairly oily as well, so they spread nicely straight from the tube. (Note: If this isn’t the case with your paints, you will want to add a bit of medium to get a mix that is mayonnaise consistency.)
Tree leaves against the sky, grass shadows, cloud shadows, etc., are examples of areas where this mixture is useful for landscape painters. Try to paint in all the details using transparent paint that you think you will want before going on to using any opaque paint--as in scumbling.
Scumble is a technique similar to glazing, except that the coating is opaque. The paint is applied with a lightly loaded brush held at a shallow angle (30 - 40 degrees up from the painting surface.) Bits of the paint below should be allowed to shine through. While most painters glaze with dark colors, scumbling is mainly used for lighter colors; especially atmospheric effects of fog or clouds. It’s also useful for suggesting masses of grass or simplifying areas that may have become too busy with detail. It can be used to slightly lighten colors or to modify the color of a glaze without completely covering it.
Scumbling should be done on a moistened surface--moistened with a glaze or moistened with a very thin application of medium if your glaze layer has dried. This way the brush does not drag over the surface, as it does in the dry-brushing technique. Moistening the canvas with medium also gives some of the benefit of the drying properties of the Liquin used in the medium and creates a chemical bond between the leaner scumble paint and the oilier (fatter) layer of the glaze.
Paint consistency for scumbling depends on how stiff the paint is, out of the tube, and what kind of effect you want. Each color has a different stiffness, and each brand of paint seems to be slightly different as well. It may be that no medium is needed at all, or a very little bit. Aim for a consistency somewhere between sour cream and peanut butter. Stiffer paint means you’ll need to scumble using a bristle brush, softer paint can be applied with a soft hair brush.
Some paint colors & their degrees of transparency:
Red: Alizarin Crimson (transparent), Transparent Red Iron Oxide (transparent), Permanent Red (transparent), Rose Madder (transparent), Quinacridone Red (semi-transparent), Cadmium Red (opaque), Rose Grey (opaque)
Orange: Transparent Orange (transparent), Cadmium Orange (opaque), Vermillion (opaque), Coral Red (opaque)
Yellow: Transparent Yellow Iron Oxide (transparent), Indian Yellow (transparent), Cadmium Yellow (opaque) (light, medium, dark), Yellow Ochre (opaque), Naples Yellow (opaque), Jaune Brilliant (opaque)
Green: Sap Green (transparent), Viridian (transparent), Olive Green (transparent), Pthalo Green (transparent), Turkey Umber (semi-transparent), Chromium Oxide Green (opaque), Permanent Green (opaque)
Blue: Ultramarine Blue (transparent), Prussian Blue (transparent), Pthalo Blue (transparent), Indigo (semi-transparent),Cobalt Blue (semi-transparent), Manganese Blue (semi-transparent), Cerulean Blue (opaque)
Violet: Dioxazine Purple (transparent), Ultramarine Violet (transparent), Cobalt Violet (semi-transparent), Manganese Violet (semi-transparent),
Brown: Burnt Sienna (transparent), Raw Umber (transparent), Burnt Umber (semi-transparent), Van Dyke Brown (semi-transparent), Red Ochre (opaque)
Black: Paynes Gray (transparent), Ivory Black (semi-transparent), Lamp Black (opaque), Mars Black (opaque)
White: Winsor Newton transparent white (transparent), Zinc White (semi- transparent), Titanium White (opaque), Flake White (opaque)
Glazes are applied with bristle brushes on canvas with medium to coarse weaves, and with softer brushes on smooth panels and portrait linen. The objective is to work the paint into the weave of the canvas and into the low points of any thick brustrokes created in the underpainting stage. Any irregularities in applying the glaze may be tapped out with a soft large brush--such as a fan blender, large mop brush, or even a makeup or shaving brush.
The consistency of a glaze should be like cooking oil or slightly thicker. It should first be applied to areas that need the most intense color and spread out to areas that need less, making use of the remaining paint in the brush. The surface should be moist when the glaze has been smoothed over the underpainting--not runny or slick. If the color is too intense, it may be removed by wiping the brush on the rag and continuing to work the paint, or by directly wiping away paint with the clean rag. Highlights that have been glazed over may be revealed by wiping with a rag lightly moistened with medium.
Details in the glazed areas are most easily painted using a mixture of the glaze colors--or any transparent colors that give you the color you want--but without any medium added. Painting this mixture into the glaze will blend the two paints so the leaner mixture (leaner meaning no medium added) will get some of the drying benefit of the Liquin that is part of the medium. Most transparent paints are fairly oily as well, so they spread nicely straight from the tube. (Note: If this isn’t the case with your paints, you will want to add a bit of medium to get a mix that is mayonnaise consistency.)
Tree leaves against the sky, grass shadows, cloud shadows, etc., are examples of areas where this mixture is useful for landscape painters. Try to paint in all the details using transparent paint that you think you will want before going on to using any opaque paint--as in scumbling.
Scumble is a technique similar to glazing, except that the coating is opaque. The paint is applied with a lightly loaded brush held at a shallow angle (30 - 40 degrees up from the painting surface.) Bits of the paint below should be allowed to shine through. While most painters glaze with dark colors, scumbling is mainly used for lighter colors; especially atmospheric effects of fog or clouds. It’s also useful for suggesting masses of grass or simplifying areas that may have become too busy with detail. It can be used to slightly lighten colors or to modify the color of a glaze without completely covering it.
Scumbling should be done on a moistened surface--moistened with a glaze or moistened with a very thin application of medium if your glaze layer has dried. This way the brush does not drag over the surface, as it does in the dry-brushing technique. Moistening the canvas with medium also gives some of the benefit of the drying properties of the Liquin used in the medium and creates a chemical bond between the leaner scumble paint and the oilier (fatter) layer of the glaze.
Paint consistency for scumbling depends on how stiff the paint is, out of the tube, and what kind of effect you want. Each color has a different stiffness, and each brand of paint seems to be slightly different as well. It may be that no medium is needed at all, or a very little bit. Aim for a consistency somewhere between sour cream and peanut butter. Stiffer paint means you’ll need to scumble using a bristle brush, softer paint can be applied with a soft hair brush.
Some paint colors & their degrees of transparency:
Red: Alizarin Crimson (transparent), Transparent Red Iron Oxide (transparent), Permanent Red (transparent), Rose Madder (transparent), Quinacridone Red (semi-transparent), Cadmium Red (opaque), Rose Grey (opaque)
Orange: Transparent Orange (transparent), Cadmium Orange (opaque), Vermillion (opaque), Coral Red (opaque)
Yellow: Transparent Yellow Iron Oxide (transparent), Indian Yellow (transparent), Cadmium Yellow (opaque) (light, medium, dark), Yellow Ochre (opaque), Naples Yellow (opaque), Jaune Brilliant (opaque)
Green: Sap Green (transparent), Viridian (transparent), Olive Green (transparent), Pthalo Green (transparent), Turkey Umber (semi-transparent), Chromium Oxide Green (opaque), Permanent Green (opaque)
Blue: Ultramarine Blue (transparent), Prussian Blue (transparent), Pthalo Blue (transparent), Indigo (semi-transparent),Cobalt Blue (semi-transparent), Manganese Blue (semi-transparent), Cerulean Blue (opaque)
Violet: Dioxazine Purple (transparent), Ultramarine Violet (transparent), Cobalt Violet (semi-transparent), Manganese Violet (semi-transparent),
Brown: Burnt Sienna (transparent), Raw Umber (transparent), Burnt Umber (semi-transparent), Van Dyke Brown (semi-transparent), Red Ochre (opaque)
Black: Paynes Gray (transparent), Ivory Black (semi-transparent), Lamp Black (opaque), Mars Black (opaque)
White: Winsor Newton transparent white (transparent), Zinc White (semi- transparent), Titanium White (opaque), Flake White (opaque)
