Paint Brush - Technical - Q&A

Advertisement

Paint Brush - Technical - Q&A
Q. Can I use my acrylic and watercolor brushes for painting with water soluble oils?

A. You may use your brushes any way you choose if you get the results you want. But your brushes will generally work better and last longer if you use them with the medium for which they were designed.
Over the years, brushes have been fine tuned by manufacturers in response to artists' requirements, and each one is made for a specific purpose. Their fibers-natural hair, synthetics or a mixture of the two-have qualities that respond to their use in very particular ways. As a result, their versatility has some limitations The two areas that most notably affect these limitations are the viscosity of the paint and the solvent you're using with the paint.
If you use paints thickly, as impasto, bristle brushes will be the most useful because they're the stiffest. So if you're using your water-soluble oils thickly, not recommend using your soft-hair water color brushes. Your acrylic brushes, however are acceptable in this case if they're synthetic or relatively stiff bristled. If you plan to use your water soluble oils more thinly, as in glazing, use soft-hair or synthetic brushes designed for oil painting.

Although the soft-hair, short-handled brushes used for watercolors may resemble those used for oils, they're not the same. Watercolor brushes are designed to store and dispense a lot of liquid, making them difficult to control in dispensing thin layers, while those designed for oils (particularly the long-handled kind) generally have flatter shapes that glaze more easily.
Soft-hair watercolor brushes may give you problems with water-soluble oils when it comes to solvents, however, These brushes are typically cleaned with watch but water-soluble oils may leave behind a film of oil on the fibers of the brushes that water won't be able to remove. if you try to use a solvent appropriate to oil-based paints-namely turpentine or mineral spirits on these brushes and then return to painting with acrylics or watercolors, your brushes may resist these water-based paints because of a solvent residue.
Ultimately, if you're really curious, the best way to understand the limitations of your brushes is to experiment with them. You may find some applications that give you unexpectedly satisfying results. But if you want longevity and consistency from your brushes, stick to the media they were designed for.

Stretching Your Framing Options
Q. Is it possible to mount paper on a canvas stretcher? I've heard that this can be done to frame oil paintings on paper supports, and I wondering if it can be done with watercolor paper as well.

A. Watercolor paper can certainly be stretched, but the most common reason for doing so is to keep the paper from buckling and wrinkling from the wetness while you're painting. The key to stretching paper successfully is how much you dampen the paper. Too much water and the paper shrinks and tears; too little and it doesn't tighten enough in drying.
Apply water evenly over the paper with a sponge or flat brush, cover the paper with a damp cloth, and let it sit for a while. Then test the wetness of the paper by bending down a corner-if it snaps back into place (retaining its elasticity) then it's not wet enough, and if it's soggy enough to bend of its own weight then it's too wet. But if the corner holds its position either straight or bent, then it has the right amount of water. Once the paper is prepared, mount it on a stretcher by folding the edges over the board and fastening them with noncorroding tacks or staples.
The paper should stretch easily, without much wrinkling and without tearing, and you'll have a smooth, tight painting surface when it dries.
Keep in mind, however that this technique for mounting paper supports should be used for the purpose of improving your painting process and not for long-term framing, whether your medium is oil or watercolor. Over time, acids from the wood can seep into the paper, causing discoloration and embrittlement. If you really want to mount your paper for framing, use a museum-quality of 100 percent rag fibers and mounting the paper by hinging it with a few strips of Japanese paper and a water-based paste such as wheat or rice paste.

Climate Control
Q, I paint watercolors in my basement, and I've discovered a dark substance growing in my yellow paint. What's the ideal humidity level for a watercolor studio and for leaving my palette open?

A. Your studio is a fine breeding ground for mold growth: damp, cool and probably dark most of the day. That's probably mold growing on your paint, and it's likely to affect all your other paints. It will affect any object that remains damp and can absorb the mold spores, including your watercolor papers, which probably have an organic sizing.
Conservators often use a fumigant to get rid of mold on a watercolor paper but not recommend that to a nonprofessional. A simple fix is to expose everything to a few days of warm sunlight; then you can brush off the mold dust that remains and wipe down your furniture with a damp rag and let it dry again. Brush off the papers, too. That will clean all but the paints, which you'll unfortunately have to discard.
A damp basement just isn't the best place for a watercolor studio, even with a dehumidifier. Central air conditioner in your basement (both supply and return air) would help, however because air conditioned air is quite dry. It's not so much the humidity that's the problem, but the humidity plus the temperature. Museums like to keep their collections at about 72 F and 50-60 percent relative humidity, so an ideal studio might shoot for these values. If possible, you should use a room on the main floor or second floor such as a dining room or spare bedroom and save the basement for something else. In any case, always cover the palette at the end of the day no matter what the environment, if only to keep dust off the paints.