Grounds - Oil Grounds

Equipment

Brush. 2" or 3" bristle.

Palette

Palette Knife. Preferably about 6" long and trowel-shaped.

Materials

Canvas. Artist's unprimed canvas, stretched on chassis, and sized with glue water.

Oil Priming. Flake white oil paint or industrial white lead paint, made of carbonate of lead ground in linseed oil.

Turpentine. Pure gum spirits of turpentine.

[p. 105]

2. Apply the thinned paint to the face of the sized canvas, with either a 2-inch brush or a palette knife. Cover a small section [about 6: by 6:] at a time. Force the paint down into the weave, so that it gets a good grip in the surface of the textile. The sides and excess margin of the canvas should be sized and primed to protect them against wear. [p. 106]

3. Before the paint sets, remove excess paint by scraping with the palette knife. The coating should be even, very thin, without streaks, and must be forced well down into the wave. Avoid leaving a scraped line where the canvas lies over the inside edge of the stretcher strips. Put your hand under the canvas and lift it away from the stretcher strip as you scrape over it. Store the remaining priming paint in a tightly covered container in order to prevent evaporation of the turpentine.

4. Allow the canvas to dry well in the light [usually three to six days in a warm dry place is enough]. Then apply a second coat of white lead, of the same consistency, in the same way as the first. Before painting on the canvas, allow the second coat to dry for at least two weeks in a place where it will be exposed to light.

5. Brushes and tools should be cleaned with turpentine or mineral spirits and then washed with soap and water in the usual way.

[pp. 105-107]

Notes
A. Since 1973 it has become nearly impossible in the United States to buy the white lead in linseed oil that was the common paint used in the industrial painting trades. Such brands as Dutch Boy white lead have disappeared from the market as a result of legislation to prevent the use of toxic paints on residential housing, furniture, and toys, where peeling paint might present a health hazard, especially to small children who might eat the paint chips. Consequently artists who wish to use an oil priming for their canvases usually must substitute another material for the industrial white lead in linseed oil. [p. 107]

Some manufacturers of artists' materials still sell flake white oil paint in pint cans, as well as in the large "pound" tubes of approximately 150 cc. capacity. It should be noted, however, that most, if not all, of these flake white artists' oil colors are ground in a safflower oil or poppyseed oil and not in linseed oil. They are slower drying and form films that may be less suitable than is flake white linseed oil paint for the ground coat of the picture. They are also substantially more expensive than was the industrial white lead in linseed oil, since they are sold for art use rather than for industrial use.

One material consisting of flake white, linseed oil, and mineral spirits, compounded specifically for priming artists' canvas, is Fredrix [Tara Materials, Inc .] oil priming lead white. It is produced in a rather liquid consistency, and it should not be further thinned when it is applied. The lead pigment often settles to the bottom of the can in the form of a hard sludge that must be mixed again into the oil. For the purpose a rigid blade, such as a wide screwdriver, is needed to break up the sludge, and then the smaller lumps must be stirred until they are completely mixed again with the oil to a smooth paint consistency. B. Glue size must have a chance to dry well [minimum 24 hours] before the canvas is primed with the oil ground.

C. White lead grounds should be dried in the light, or they will darken appreciably.

D. If white lead oil primings have darkened from being stored in a dark place, they may be restored to their original condition by exposure to sunlight for a few days.

E. If primed or sized canvas is dented by accident, and the resulting bump cannot be eliminated by stretching that section with pliers, moisten the area carefully from the back of the canvas with a damp sponge or rag. Often the moisture alone will straighten out the bump. If it does not, moisten it again and restretch that area.

F. All linseed oil grounds yellow slightly with age.

G. Zinc white pigment, ground in linseed oil [such as zinc white artists' color or a commercial zinc paste similar in consistency to the industrial white lead paste], may be added to make a whiter ground. Such mixtures should not exceed 1 part zinc white to 2 parts white lead. This mixture will yellow less than will the white lead ground. It will dry much more slowly and will yield films that are less tough and less flexible than those of white lead.

H. Other canvas-priming materials are compounded with titanium white and linseed oil. These have the increased whiteness of titanium. Furthermore, titanium is not toxic, whereas flake white is poisonous. However, the film made by titanium and linseed oil is less flexible than that made by flake white and linseed oil, and the titanium in linseed oil will dry more slowly than will the flake white in linseed oil, unless the manufacturer adds driers. [p. 108]

I. Small amounts of oil color may be mixed with the white paint to produce a tinted ground, but a white ground is best for keeping the luminosity of the picture. If a toned canvas is desired, it is best obtained through the use of an imprimatura.

J. The date of application of the second coat should be noted on the edge of the stretcher to prevent painting on the canvas before the ground has dried thoroughly.

K. White lead is toxic. The painter should keep the lead priming away from food, cigarettes, and cuts and should wash carefully after using the lead compound.

[107-109]