Q. What is the proper way to dispose of art materials?
A. On a day-to-day basis it's wise to dispose of paints, waste water and solvents so they won't get into your sewer system and cause blockages or exacerbate environmental problems. Go to this site for instructions on handling rags, solvents, liquids, aerosols, glues, metals, paints and more.

Q. What are water-mixable oil paints?
A. It is very easy to paint and clean up using these paints without having to use turpentine or other potentially hazardous solvents. Using mineral spirits for clean-up is a more involved process and includes concerns about disposal of the hazardous solvent at the end of the painting period. The paints seem highly pigmented and have that nice buttery quality found in traditional oils. Drying time for water-mixable oils is about the same as for regular paints, and the working characteristics and appearance of the finished painting are also similar. They can be used with traditional oils and alkyds, but I feel that such mixing makes clean-up a little more difficult. Several companies make water-mixable oils, such as Winsor & Newton, Holbein and Grumbacher. It may not be a good idea to mix brands, as each company has a different process for making the oils compatible with water. Consider taking water-mixable oils when you travel to workshops or vacations. See my book review of Painting With Water Soluble Oils by Sean Dye.

Q. What is the white powdery substance I find on some of my watercolors?
A. It is either mold or mildew. Some colors are more likely to do this than others, especially when left in a closed palette over a long period of time. Phthalocyanine green seems to be one of the chief offenders. I wipe the powder off with a cotton ball dipped in rubbing alcohol and spritz the palette with alcohol to kill stray spores. I've only had this happen two or three times in thirty years, so I don't consider it a major problem. It doesn't seem to affect the color or grow on the painting. If anyone has had a different experience, please let me know.

Q. Why are some so-called "transparent" watercolors actually opaque?
A. It's the nature of certain pigments, such as cerulean blue, the cadmium colors, and some of the earth colors to be denser and more opaque than others. This is also true in other paints than watercolors, with the exception of gouache, which has opaque matter added to the pigment to give it covering power. Watercolors are traditionally called "transparent" because they are diluted more than other paints and applied in a fluid manner so the support, usually white paper, will reflect through the paint layer. Other media are generally applied more heavily so the paint layer has more body and covers up the support, even though the pigment itself may be somewhat transparent. These pigments are frequently used by oil and acrylic painters for glazing. However, regardless of the nature of the pigment, brands may differ greatly both in hue and transparency because of different manufacturing processes. For instructions on testing your paints for transparency, see my project, Testing Paints for Transparency. For more on transparency see pp. 38-39 of Exploring Color.

Q. What is the difference between dyes and pigments?
A. Dyes, colorants in which the coloring matter is dissolved in liquid, are absorbed into the material to which they are applied. Pigments, consisting of extremely fine particles of ground coloring matter suspended in liquid, form a paint film that is bonded to the surface it is applied to. Dyes are sometimes precipitated onto an inert base and ground into pigments. Traditionally pigments have been more lightfast than dyes, but the advent of synthetic paints has seen much improvement in the lightfastness of dyes and inks, as well as pigments.

Q. Is there any way to keep new paint from shooting out of the tube the first time you open it? A. Unfold the crimp at the bottom of the tube just once before opening the tube to relieve the pressure. After squeezing out your paint and putting the lid back on, re-fold the bottom of the tube. Kathy Roush posted this tip on an art newsgroup.

Q. Is it safe to put my acrylics in the freezer to keep them moist? A. No! Paints of any kind should not be subjected to freezing temperatures in the freezer or in your car overnight in the winter. Freezing might affect the chemistry and handling properties of the paints. It won't hurt your paints to be stored in the refrigerator, though, if they are tightly sealed.

Q. Where can I find information on pigments and paints?
A. In my opinion, the most comprehensive for watercolor is Hilary Page's Guide to Watercolor Paints. Another recent book that is very informative is David Pyle's Paint & Colors: What Every Artist Needs to Know, new this year. The book is comprehensive, covering most media and including the history of pigments to the behavior of paints and safety issues.

Q. What's the difference between artist-quality and student-grade paints?
A. As a rule, the student grade will have a considerable amount of filler or extender added to the paint, which lowers the amount of actual pigment in the color. The result is a color that is weaker in tinting strength than the same color in artist's quality. It may also make the paint more opaque or chalkier than the better quality of paint. With some student colors, the original pigment has been replaced by a synthetic substitute that may not be an accurate replication of the true color, both in appearance and handling characteristics. For example, if Cobalt Blue is made with the less costly Phthalocyanine Blue, it will be much greener and have staining properties that true Cobalt Blue doesn't have. It's easy to understand why people begin painting with student colors (and there are some good ones on the market), because of the big difference in price, but it's usually advisable to upgrade as soon as possible, if you really want to get good results from your paints. One way to tell the difference between them is in the pricing structure: student paint tubes will usually be priced the same throughout the line, while artists' colors are priced according to the cost of the pigment materials and manufacturing processes that go into making the paint.

Q. Why do you use Alizarin Crimson, which is a fugitive color?
A. Alizarin Crimson isn't rated "fugitive" by most manufacturers--it's "moderately durable." I tested several brands of Alizarin Crimson in a south-facing window for three-and-a-half years and noticed a barely perceptible shift in color after nearly three years, hardly worth mentioning. In this same window test there were colors that faded noticeably within two weeks and eventually nearly disappeared. Others began to show fading in about two months and then stayed about the same for the next couple of years. I have never noticed a change in the paintings I've done using Winsor & Newton watercolors, although I've heard that some student brands are less reliable. I recommend all artists conduct their own tests and decide for themselves whether they feel comfortable using certain colors. (Believe it or not, one of the least fading colors in my test was Holbein's Opera.) For your own peace of mind you may want to try one of the newer Permanent Alizarin Crimsons, but the colors aren't as luscious as the real thing. Let's Talk about your experiences with lightfastness.

Q. Are colors with the same name alike in different brands?
A. Colors may differ greatly from one brand to another, even if they're made from the same pigments, because the formulas and other ingredients, as well as the manufacturing processes, are probably not the same. Ask your dealer to show you painted chip charts, rather than printed charts, so you can compare the actual paint colors.

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