by Jane Sutherland

Repairing a Tear
One of my finished oil paintings has a tear on the canvas. What is the best way to repair it? Would I glue a piece of canvas to the back? What kind of glue should I use?

In the past, the best way to repair a tear in a canvas was to glue a piece of similar canvas onto the back side of the surface using a water-based glue, such as rabbit-skin glue, or a wax resin. Today synthetic adhesives are more commonly used for repairing small tears in a canvas. Use a stiff-glue gesso to fill in the gaps and then in-paint—the technique of modifying a painting in an undetectable way—to hide the repair. Although it is acceptable to attempt a repair on your own canvas, an art conservator should be consulted for repairs on someone else’s work. 

Manipulating Water-Soluble Oils
I recently purchased water-soluble oil paints, and I’m having trouble keeping my colors clean and nonsticky. Should I use water to thin the paints? Can I use a medium with them?

Water-miscible (or water-soluble) oil paint performs just the way regular oil paint does, but it is miscible with water instead of turpentine. This type of paint shares similar properties with traditional oil paint, including a buttery consistency, slow drying time, and use in the fat-over-lean principle. It is also compatible with the mediums and traditional techniques of oil-painting methods; additionally, you can mix this paint with conventional oil paint and still use water as a solvent and to clean up. When handling these paints it’s important to keep the proportion of traditional color or medium to only 30 percent. When the proportion of the water-miscible paint is less than 70 percent it is necessary to use a traditional solvent, such as turpentine. Although not every oil color is available in water-soluble form, there are at least 60 colors on the market, including all the earth colors.

Drying Time of Alkyds
I understand that alkyd paints dry faster than regular oils. Do you know how much faster?

Alkyds dry on the surface in less than 24 hours and are completely dry and ready to varnish in about two weeks, which makes them slower drying than acrylic but much quicker drying than oils. Alkyds have the same pigments as oils and the same binder, natural linseed oil. What makes alkyds different is that the linseed oil binder is synthetically modified and converted into a new substance that enables the paint film to dry quickly and evenly. Although alkyds are designed to handle just like oil paints, as are water-miscible oils, the modifications of the traditional medium may take getting used to for someone who regularly works in oil.

Smoothing Out a Surface
I recently painted several flower arrangements on a black background using a minimum of Galkyd and Gamsol. Once the painting dried, I noticed that some parts were shiny, some were matte and smooth, and others were chalky. How can I achieve a more even surface?

It is not unusual for paintings to dry matte in some areas and lustrous in others, especially if it’s being worked on over a period of time and if paint from a previous session is used. Paint that is exposed to air overnight begins to dry out, leaving the paint with less binding oil, which results in a dull or chalky look. Also, because some pigments absorb more oil than others, it is possible that the surface will have uneven drying characteristics depending on how much or little medium (which makes paint more flexible and improves handling qualities) or solvent (which modifies the thickness of the paint for easier manipulations) is used in different sections of the painting.

Another cause of a sunken-in appearance can be a ground that is either too absorbent or unevenly absorbent. Try adding a very thin film of retouch varnish to the dull, chalky areas to bring them back to life. Retouch varnish is only a temporary varnish because a painting requires at least six months of drying time before a coat of final varnish can be applied. You can achieve a unified sheen and temporary protection of the surface with a thin film of retouch varnish. It’s important to note that wax varnish may at first appear dull and lifeless but, if you gently buff the surface with a chamois or soft cloth, it is possible to achieve a lovely satin finish.

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Comments

My friend gave me a painting to stretch that had been done by his late father. In the corner next to the signature the canvas is trimmed so closely that I don't have enough to stretch over the strips. How can I add additional canvas to the piece without harming the original artwork? (The original canvas is also somewhat brittle/dry.)

Regarding "Manipulating Water[-thinned]Oils: "turpentine" is mentioned as a thinner/solvent.

If "turpentine" means "gum turpentine," readers should know that this is a toxic solvent and can be replace for every studio operation except making damar varnish by odorless mineral spirits. (Odorless mineral spirits is also harmful