ACRYLIC POLYMER Acrylic polymer paints were initially developed as industrial paints that were first used by artists after WW2. Acrylic polymer paints are composed of pigment suspended in acrylic resin (Rhoplex). When wet, polymer paints are soluble in water, but dry to an insoluble hard plastic. Acrylic polymer paints (commonly called acrylics) are extremely versatile and can be applied with a wide range of textural effects. To create bled or poured effects, polymers can be directly applied to raw, unprimed canvas. Oil paints cannot be used in this way because acids naturally present in the oil will eventually cause canvas to deteriorate. Because acrylics are fast drying, thickly painted works can be completed quickly. If necessary, an acrylic retarder can be mixed with acrylic paints to help slow their drying. Acrylics are well suited for building transparencies and/or flat color, rather than for painting that requires delicate control and blending. Acrylics will peel from glass or other non-porous surfaces but bind well to cloth, wood, and unglazed ceramic. Polymer medium - is the binder of acrylic paints that can be mixed with polymer colors to create smoother consistencies and glazes. A polymer medium (matte or gloss) has a milky color when wet, but dries completely transparent if used properly. Gloss medium can be used as a final varnish over acrylic painting. Matte medium works the same way, but has a duller finish. Polymer medium may dry cloudy when brushed continuously while drying or when diluted with too much water (not to exceed 25% water to medium). Iridescent medium is available for "metallic" color mixtures. An iridescent color can be made by mixing a transparent acrylic color with this medium. Polymer mediums can also be used as adhesives and work well when incorporated in mixed-media and other techniques. Polymer mediums are ideal for use in collage, or attaching tissue paper to the surfaces of canvas or board. Oil paint, oil glazes, and oil sticks can be applied over any acrylic surface. Chalk pastels (pigment plus clay) can also be used in combination with acrylic or oil paints. Acrylic Polymer Gesso - is used as a primer (or ground) for both acrylic and oil. Acrylic gesso is usually opaque white, however black gesso is available for opaque black grounds. Color gesso can also be purchased for artists interested in using color grounds. Taping - Sharp edges can be made in acrylics without the paint bleeding or crawling under masking tape. Artists seal the masking tape edge or edges with polymer medium, allowing it to dry, then painting in the masked-off areas. Textural effects with acrylic mediums Along with gloss, matte, and gel medium, acrylic polymer gesso can be mixed with aggregate materials such as sand, marble dust, or cement to produce textural or sculptural effects. Gel medium - Similar to polymer medium, polymer gel can be mixed with varying amounts of acrylic colors to create opaque or transparent impasto effects. Used by itself, gel medium dries transparent. It is well-suited for mixed media techniques and can be used as an adhesive or applied on top of collage, modeling paste, cloth, wood, unglazed ceramic, sanded metal, or any acrylic surface. Gel medium is now available in matte, gloss and opaque finishes. Modeling Paste - Modeling paste is a blend of acrylic polymer and marble dust. Textural effects can be created with modeling paste directly on gessoed surfaces. However, modeling paste may crack on flexible surfaces (such as canvas) unless gel medium is added. Modeling paste is opaque and is primarily used to create textured surfaces before paints are applied. Generally speaking, acrylic paint is not mixed with modeling paste. BRUSHES Brushes come in a wide variety of shapes and sizes, and are designed to do different things with paint. White bristle or "hog's hair" are the most popular stiff brushes used by oil and acrylic painters. This natural bristle comes from the coarse hair found on the backs of pigs. Because these brushes are stiff and "springy", thick paint can be pushed and blended on the surface. Sable brushes are the best of the soft bristle brushes. The hairs of this brush are reddish in color and taper to a natural point. These brushes are ideal for delicate and controlled paint manipulation, such as glazing, and like white bristle, are "springy" for easy control. Sable brushes are very expensive and should be treated with care. There are synthetic and sable blends called "sabeline" available today which are much cheaper and do a good job as a soft bristle brush. Synthetic white bristle brushes share many of the characteristics of both sable and natural white bristle. Unfortunately, these brushes do not work well with oil painting because oil paint tends to bead-up in the synthetic hairs. Like the sabeline brush, there are natural white and synthetic bristle blends available to the artist. Paint brush styles Styles of brushes also vary depending on their use. The round is good for making thin drawing lines or for painting details. The brushes used most frequently in oil and acrylic painting are flats and brights. Both brushes have a straight or chiseled end, though brights tend to be shorter in length. White bristle flats or brights hold a lot of paint and are used to cover large areas quickly. The bright is the best blending brush available. Filberts are similar to flats and brights, except that they have rounded corners which create a different edge on the paint stroke. All brushes can be turned in a variety of directions to create different types of brushstrokes. Using a paint rag A lint free rag can be used to make marks or pull the paint from the surface. A rag also erases large or small areas of paint. A brush is used in combination with a rag to control the amount of paint and liquid in the brush. A rag is an essential painting tool. The best rags are made from cut up T-shirts, because they are absorbent, soft, and lint free. Keeping brushes clean For oils, keep brushes in a tin can or glass jar that contains odorless spirits. To keep brushes from resting in paint sediment that has settled to the bottom of the can, place a piece of wire window screen about 2 or 3 inches from the bottom of the can. (A crumpled wad of window screen that fits snugly at the bottom of the can works well. Make a smooth "face" for the brushes to rest against). The rough screen helps to clean brushes and keeps them away from the sediment. Brushes used with acrylic paints or mediums should be kept in plastic or glass jars containing cold water. Tin cans rust and can alter the color of paints. Brushes must be kept in water when not in use and cleaned with cold soap and water. Any acrylic residue left in brushes will dry to a hard, insoluble plastic. Palette knives are used to mix paint on the palette. The best palette knife is bent, which helps to keep knuckles from getting in the paint. Painting knives are used as actual painting tools to create textural effects and are especially useful for thick applications of paint (impasto). GETTING STARTED Step 1 -- Sketching directly onto a ground with diluted paint is the most immediate and will give you truer colors. Thin paint with a solvent (turpentine or OMS), or an oil medium that contains mostly solvent and very little oil (or in acrylics, thin with water). The color used for the sketch can vary -- some teachers recommend using neutral browns, such as burnt umber or burnt sienna. Others suggest more vibrant colors ranging from blues to greens. Still others recommend using ivory black. Regardless of the sketching colors you choose, it is important to use a color that creates a wide range of values. Avoid slow-drying colors -- in oil, the "browns" dry very quickly and can be covered usually in a day or two. Standing away from the painting during the sketching process will allow you to "map" out the composition quickly. Shade in areas and use a paint rag (with a solvent, if necessary) to remove or erase paint. At this point, it isn't necessary to have a meticulous or perfect drawing; in fact, this wastes time, because you will be eventually covering the sketch with additional layers of paint. If you must, sketch with pencil, chalk, or pastel. However, a careful, tightly rendered drawing will be lost when you begin to layer your paints. Shade in areas, but keep the drawing loose. Don't use charcoal or other dark drawing materials. If the drawing materials used are too dark, they will mix with your paint and cause it to become dark and muddy. If you choose to draw in pencil or another "dry" medium, liquefy the material by adding a thin oil or thin acrylic painting medium (depending on the type of paint that you use). Binders in the medium help the pigment stick to the surface. Step 2 (Blocking-in color) -- This may be the most important step in painting. The most efficient way to achieve a good composition and unity in a painting is to initially develop large color areas. For oils, block in areas with paint that has been thinned with an oil medium that contains mostly solvent. In acrylics, use paint that has been thinned with water or a polymer medium. Use only necessary colors. Block in the entire surface, including the "background" and negative areas. This should be done very quickly and with a large brush. You should be standing during this process so you can get back and see the "whole" surface area, rather than getting caught up with details. Consider color harmonies or color schemes in the work. Step 3 -- After the overall color plan is completed, the next layers of paint, which might include blending or dabbing can be started. Working from thin to thick is a sound rule. Some painters do a lot of blending. This is achieved by applying patches or dabs of paint over an area before they begin blending in the paint. Other painters try to build up fresh, unblended dabs or strokes on the canvas. Impasto paint applications may also be used at this stage of the painting. In oil paint, apply more oily layers of paint over less oily areas (fat over lean). Otherwise, your painting may crack. This problem does not occur with acrylics, because they can more easily expand and contract. After the initial sketching and blocking in layers, use a medium that has been mixed in advance for the remaining painting. This can alleviated many problems with consistency. Avoid mixing pure oil or pure solvent with your paint in these subsequent layers. Step 4 -- Final stages Because oily layers should be applied over leaner layers of oil paint, transparent glazes made with an oil medium generally should be applied during the final stages of an oil painting. Glazes can create transparencies in specific color areas to unify the painting. They may be applied in one or more layers over transparent or opaque paint. Using glazes in this way differs from traditional glaze painting discussed below. Acrylic glazes can be applied on acrylic painting at any stage of the painting. Notes on starting a painting Because oil paint lends itself to blending, it an excellent paint to use if you are working in a realistic style. Oil will often dry in one or two days, however, so it makes sense to finish particular areas in one sitting. If the paint is allowed to dry on an unfinished area, wet paint will have to be reapplied in order to complete the work. An oil painting medium will increase the creaminess and fluidity of the paint and can slow the drying time, if desired. Using reflective colors at this stage will give a unified quality to the work. This is achieved by "unloading" varying amounts of one color to another color area. Reflective color use is only one option, however. Some artists prefer working in pure areas of color. This often lends vibrancy to the work because of contrasts in the individual color areas. Sometimes work done in this way may have a fragmented appearance in color, not unlike what one might associate with "coloring". Areas may seem unrelated or filled-in. Limiting the palette, repeating the colors in the work, or using limited amounts of reflective color will help. Creating powerful value contrasts by darkening and lightening colors will also give the painting "structure" and therefore, give the work more coherence. The danger of adding black or white to color is that the relative purity of the color diminishes. One should also think in terms of contrasts in color, such as complementary colors and other color schemes, to increase the vibrancy of a work. Perhaps one of the most effective ways of developing space in painting is through the use of cool and warm colors. Cool colors recede in space, i.e., blues, violets, blue green and blue-violet, while warm colors appear to push forward in space, i.e., yellows, oranges, reds, red-oranges and yellow-oranges. The impressionist painters used cool and warm colors to create ranges of depth rather than relying on tints and shades to create spatial contrasts, as was often done by the traditional academic painters. The impressionists often used white to lighten colors, however. Drying time is effected by the amount of oil present in the paint or painting medium. Painting mediums made with a higher proportion of oil will cause the paint to dry more slowly (an often desirable effect). Some colors, such as titanium white or ivory black, contain more oil and therefore dry more slowly. Some manufacturers mix more oil into their paints than others. The thickness of the paint also effects drying time. Oil paints dry more quickly in warm conditions, as well. In the summer, oil painters will sometimes warm their paintings in direct sunlight to accelerate the drying time. Because of all these factors, it is often very difficult to predict the speed at which an oil painting will dry. Drying can be somewhat controlled by the type of oil used in the medium -- for example, sun-thickened oil dries rapidly and is useful in glazing or transparencies, because layers can be covered very quickly (sometimes in 24 hours). Stand oil is slow drying, so areas stay "workable" for much longer. Stand and sun-thickened oil are ideal in painting mediums and can be mixed together for even greater control of drying. A tiny quantity of cobalt dryer can be added to a medium made with stand oil to increase its drying time. Mediums made with refined linseed or safflower oil are runny and harder to control than those made with stand or sun-thickened oil. Refined linseed oil can be mixed with either of the thicker oils if necessary. Commercially produced mediums made with alkyd resins make oil paints dry more quickly than mediums made with traditional drying oils. Acrylics dry more quickly than oil, so learning how to layer wet paint over dried areas is key to understanding this medium. To increase the fluidity of the paint, and add to the transparency, add water (no more than 25% water) or mix in any proportion of matte or gloss medium. Matte medium has a duller finish than gloss. The type and style of painting will ultimately determine which medium to choose. On very dark paintings, gloss medium will cause the surface to be highly reflective. This can sometimes make the painting difficult to view in some lighting situations. It is also important to work from thin to thick in acrylics, especially if you want to use impasto techniques. Thick acrylic cannot be removed or changed after it has dried. Oil glaze paintings -- A traditional oil glaze painting requires a different approach than the opaque painting described above. Artists first complete a thin tonal underpainting using a thin glaze medium with black or brown oil paint. This tonal painting is traditionally called a grisaille from the French "gris" (meaning gray in English). Layers of transparent color (see Pigments for a list of transparent oil colors) are mixed with a painting glaze medium and applied over this fairly accurate and exact underpainting -- allowing the "drawing" to show through the glazes. Many glazes can be layered on top of one another. The intense luminosity of an oil glaze painting is created by light reflecting through the transparent layers of thin glazes. When done correctly, oil glaze paintings are incredibly luminous. Acrylic glaze paintings -- An acrylic glaze painting is created with a similar step-by-step process used in an oil glaze painting. Acrylic glazes can be made with either gloss or matte medium. Small amounts of transparent acrylic color can be added to the acrylic medium. Use limited amounts of water, as it will reduce the transparency and perhaps even make the color cloudy. One disadvantage to using acrylics is that wet polymer mediums lighten the appearance of colors, and the resulting dry glaze can differ dramatically from the wet mixture. More precise glaze colors can be tested, then measured and premixed and stored in airtight containers. An advantage is the quick drying time, so subsequent layers can be painted in a manner of minutes rather than overnight. Combining oil and acrylic -- Painters can begin a painting in acrylic and complete it in oil glazes. The oil glazes bring a rich, luminous quality to the acrylic underpainting. Cleanup Use odorless thinners and soap and cool water to clean oil paint from brushes, etc. Hand cleaners such as Goop work well for cleaning oil paint brushes because of their grease-cutting properties. Mineral oil will also clean oil paint from brushes. Murphy's Oil Soap works well for cleaning brushes and removing oil paint from clothing, although Murphy's Oil soap will swell the bristles of paint brushes if they are soaked. DO NOT DISCARD OIL OR OIL SOLVENTS IN THE SINK. DOING SO WILL CLOG THE SINK. Use plain soap and cool waterGROUNDS A ground is used with both acrylic and oil paints to create a nonabsorbent surface on which to apply paints. The ground ensures the proper binding of paint to the surface, helps to separate mildly acidic oils from the support, and allows the painting to retain its brilliance of color. Grounds are usually white, enabling light to reflect from the surface. Before the use of acrylic gesso, artists sized rigid and flexible supports before applying the ground (see preparing traditional supports). Acrylic gesso functions as both a size and a ground, making this a one-step preparation rather than two. According to the excellent painting text, Painting as a Language by Jean Robertson and Craig McDaniel, priming is the accurate description of the entire process of preparing a support -- either the traditional two-step or the acrylic one-step procedure. Nonetheless, acrylic gesso is often referred to interchangeably as both a ground and primer, presumably because it is a one-step, simple preparation. What is important to remember is that there are several ways of preparing supports and that artists should use surfaces on which: 1. paint can properly and permanently bind 2. pigment and binder will not be absorbed CREATING A GROUND FOR CANVAS OR BOARD Most painters use gesso as a ground for their paintings. An Italian word, "gesso" means gypsum and was originally used to refer to the plaster surfaces on which fresco painters executed their work. Eventually this term was used to describe other painting grounds, such as gesso sotile, and most recently, acrylic gesso. The most popular ground used today is acrylic polymer gesso because of its versatility, easy use, rapid drying, and flexibility. Acrylic gesso is considered adequate as a ground for oil paints, although this is somewhat controversial. Some oil painters and technical experts argue that the flexible acrylic surface will cause oil paint (which dries brittle and becomes even more so over time) to crack. (This would also apply to any acrylic surface, including acrylic paints, gels, mediums, and modeling paste). In addition, acrylic gesso is somewhat absorbent, causing some colors in oil paint to dry matte or dull. Painters can add small amounts of stand oil or oil medium to a rag and rub the dull area to restore is color brilliance, a process known as "oiling out". Using traditional grounds can also prevent oil paints from drying matte or dull. Many oil painters prefer traditional surfaces, because they are almost completely nonabsorbent, stable, and permanent. Alkyd-based gesso, when used with rabbit skin glue, will also create an excellent, nonabsorbent and stable ground for oil on canvas. Acrylic gesso has been used for fifty years and many oil painters, nonetheless, prefer this ground over others because of its convenience. Manufacturers label this gesso as suitable for acrylic, tempera, and oil. Acrylic polymer gesso works as both a size (see below) and a ground, because it fills in holes and creates a barrier between the paint and the canvas. Because acrylics do not effect the integrity of the raw canvas or board, some acrylic painters even eliminate the use of an acrylic gesso ground in order to attain bled effects. However, most acrylic paintings are done on acrylic gesso grounds. Acrylic gesso is soluble in water, so cleanup is very simple using soap and water. Polymer gesso, paints, and media must not be allowed to dry in brushes, as they will harden to insoluble plastic. Ideally, acrylic gesso should be applied in thin layers, the first being the thinnest. A dilution of 2 parts gesso to 1 part water brushed in a direction that follows the weave is good for the first coat. After the first coat is dry, another thicker coat (3 parts gesso to 1 part water) brushed perpendicular to the first should follow. Each dry coat should be lightly sanded. Several more coats should be applied in the same manner. Four or five thin, sanded layers of gesso make a far superior surface than one or two thick coats. Rigid supports, such as masonite and wood panels should be prepared in the same way, though coatings should be applied to both sides of masonite panels, if the panels are not glued to a frame. This will prevent warping. Acrylic gesso may be mixed with various acrylic media, such as matte or gloss medium. This creates a less absorbent surface which lends vibrancy to color and prevents brushes from "dragging" across the surface. To create an extra smooth surface on a stretched canvas using an acrylic gesso ground, a squeegee can be used to apply the gesso to the surface. Pour an adequate amount of gesso onto the middle of a canvas that is lying flat and face up on a protected floor or table. A squeegee can be made from a piece of mat board or other rigid material. The gesso is squeegeed evenly over the entire surface making sure that ridges and drips are smoothed. Excess gesso can be gathered on a corner or edge and pushed into a gesso container. Put the canvas upright for drying to prevent sagging. Sand and reapply subsequent coats also with a squeegee. Colored grounds -- tonal or imprimatura Artists often prefer working on a colored or neutral colored ground. Forms can be developed easily on these surfaces, and color can appear more vibrant. Tonal grounds are flat and opaque . Color is mixed with white paint to create the opacity. Transparent color applied to a ground is called an imprimatura. This flat, transparent colored layer allows light to pass through to the original surface which reflects back through subsequent layers of translucent or transparent paint. Thin washes of acrylic can be applied to create a transparent color on an acrylic gesso ground. Replacing the water with at least 75% matte medium will improve the transparency of the imprimatura. Oil paint thinned with odorless mineral spirits (oms) or an alkyd medium can be painted on acrylic gesso surfaces as well, provided the remainder of the painting be done in oil. On oil grounds, such as alkyd gesso, lead white, or gesso sotile, oil paint washes thinned with either an oms or an alkyd medium can be painted on the surface and dried before continued painting (see below). Alkyd paints work well as colored grounds for oil paints because they dry quickly. Oil-based grounds, including materials containing alkyd resins, are not suitable for acrylic or water-based paints. Neutral grounds were often used by painters, such as Rembrandt or Frans Hals, who were interested in creating dramatic lighting effects or chiaroscuro which is easier to achieve on neutral colored surfaces. Carravagio is perhaps the artist best known for using this dramatic effect. Textured grounds for both oil and acrylic - Painters can work on textured surfaces made from acrylic mediums. These textured grounds are considered suitable for oil, as well as acrylic (see Textural effects with acrylic mediums). Preparing traditional supports for oil painting Sizing - Before the use of acrylics, painters sized both flexible and rigid supports. (Sizing is not necessary when using polymer gesso as a ground for either oil or acrylic painting). Sizing protects the raw canvas or board from acidic oil-based grounds or paint. Sizes also fill in holes in the canvas weave and grain of the wood. When glue size is applied to stretched canvas, it becomes very tight. Most sizes are made from animal hide glue, the most common of which is rabbit skin glue. Rabbit skin glue crystals are available from art supply stores. Crystallized glue (the size of crushed gravel) must be soaked overnight before preparing the size. Granulated rabbit skin glue crystals don't have to be soaked and can be prepared immediately. The crystals are dissolved and melted into heated water (the glue should never be boiled). The hot, liquid glue is brushed (2"- 3" wide) onto the canvas, wood, or masonite. The glue should be brushed into the weave of the canvas. Brush a thin layer, starting from the center and working outward. As the glue cools it will begin to congeal. You may reheat the glue size in a saucepan to apply subsequent layers (usually two coats). Masonite and solid wood panels should be sanded prior to sizing to assure proper binding of the glue. Oil-based grounds for oil painting - Some oil painters prefer traditional methods for preparing canvas. Though time consuming, these methods create excellent nonabsorbent surfaces for oil painting that allow oil paints to properly (and permanently) bind to the ground: For oil on canvas - Begin by sizing the canvas with two coats of rabbit skin glue. After the glue size is dry, apply with a brush or painting knife a smooth layer of oil priming white or flake white. The priming white should be thinned with turpentine to the consistency of sour cream. Allow the surface to dry for several days or until the priming white is dry to the touch. A second coat of the same consistency of priming white may be applied and then dried for several weeks. Placing the canvas in the sun helps to speed up the drying time. Priming white and flake white contain lead pigment and are poisonous, so care in their use is extremely important. Grounds for rigid supports - In addition to acrylic gesso grounds, traditional gesso grounds, known as gesso sotile can be applied to pre- sized masonite panels. Gesso sotile raises the grain on birch plywood panels, so this method should be reserved for use with masonite. Basically, gesso sotile is a mixture of dry white pigment and warm, liquid rabbit skin glue at a ratio of about 1 or 2 parts pigment to 1 part glue. There are several white pigments that can be used in this mixture, a typical one being a 50/50 blend of titanium or zinc white pigment and French chalk or whiting (calcium or magnesium carbonate). The pigment is mixed directly into the hot, melted glue. The warm gesso is applied to the sized masonite in one direction. After the ground is dry, it should be sanded lightly to remove roughness. Several coats of warm gesso should be applied (with sanding in-between) in directions perpendicular to each other. Alkyd Gesso - Gesso made from alkyd resins and white pigment can be used for an oil painting ground on either canvas or rigid supports. Canvas supports should be sized with rabbit skin glue before applying the alkyd gesso. This gesso can, however, be applied directly to rigid surfaces. Each coat of alkyd gesso (lightly sanded) will dry overnight. An oil painting can be started after two coats, so relatively speaking, preparing a surface with alkyd gesso is much faster than with traditional glue size and lead white techniques. Alkyd gesso is nonabsorbent and will allow oil paints to dry glossier and more vibrant. to clean acrylics. Dishwashing detergent or liquid hand soap work fine. Water can be poured down the sink, but thick chunks of acrylic paint should be thrown in the garbage. Place the brush in the palm of your hand and swish the brush to remove the paint. Run water through the brush and repeat the process until the water runs clean. Reshape the brush with your fingers and store in a jar or can handle-side down. OIL PAINT Oil paint became widely used in the 15th and 16th centuries, although oil was mixed with egg tempera in medieval painting. The early oil painter was given the advantage of blending and mixing paints directly on the support rather than carefully layering them, as was the case with egg tempera. Because oil paint dries slowly, surfaces can be worked for hours or sometimes days. The key is to keep the paint fresh and alive by not overworking and creating muddy color. Artists can easily change areas by wiping with a turpentine rag or scraping with a painting knife. Oil paint must be used on top of a prepared surface (see Grounds), in order to create a barrier between the acidic oil paint and the support. The traditional solvent for oil paint is turpentine. Turpentine is used in traditional oil painting mediums, especially those that contain damar varnish. Unfortunately, turpentine produces noxious fumes. Mineral spirits or paint thinners also produce dangerous fumes and should only be used in well-ventilated areas. Odorless mineral spirits (OMS) is now available, which dramatically cuts down on noxious fumes (see solvents). Popular brands available locally are Turpenoid and Houston Art (Mona Lisa). Oil paints cannot be mixed with water or water based paints, including acrylics. Some artists, however, layer oil paints on top of dry acrylic paint or gesso, which can create interesting effects. Acrylics cannot, however, be used on top of oil paints because they will not properly bind to the oil surface. Drying Oils - Vegetable oils like cold-pressed safflower oil or refined linseed oil are used in artist's oil paints because they are non-yellowing, quick drying, and durable. Boiled or raw linseed oil available in hardware stores is unsuitable for artist's oils, because they are heat-treated and will yellow the paint in a relatively short period of time. Artist's Refined (cold-pressed) linseed oil This is the most widely used oil in artists' paints. It is light amber in color and slow- drying. Poppy Oil A slow drying oil, this medium is used in alla prima techniques. Poppy oil is not as durable as linseed oil and can crack more easily, however. Cold Pressed Safflower Oil Similar to linseed oil, safflower oil is very clear and non-yellowing. The best sources for cold or expellor pressed safflower oil are health food stores where it can be purchased much more cheaply than at art supply stores. Avoid mechanically pressed (heat treated) safflower oil found in conventional groceries. These oils will yellow. Stand Oil Made from linseed oil, stand oil is thicker, which improves paint flow. Stand oil is thickened by heating it under controlled conditions that make the oil non yellowing. This oil gives a glossy-like finish which does not show brush strokes. Stand oil is excellent when used in glazing mediums. It dries slowly. Sun-thickened Oil Sun-thickened oil is prepared by naturally thickening linseed oil in sunlight. Sun- thickened oil is similar in consistency and workability to stand oil, however, sun- thickened is fast-drying -- in fact mediums mixed with this oil can dry within a day. Stand and sun-thickened oils should be mixed as a painting medium before being used with oil paint. When using oil paint, the first layers should contain less drying oil than the subsequent layers. This is the principle of fat over lean. A painting should be planned so that the underpainting is lean or low in oil content. These initial layers should be thinned with a medium composed of large amounts of solvent with smaller amounts of oil. Oil expands and contracts as it dries (oxidizes). If lean (low oil) paint is brushed over fat or oilier paint, the fat area's flexibility underneath may cause the lean (and more brittle) layer on top to crack. Underlayers which are not completely dry also release gases that will crack a more brittle, less oily overlayer. OIL PAINTING MEDIUMS Homemade oil mediums Oil paints may be thinned with a mixture of oil and turpentine. However, it is best to premix an oil painting medium beforehand to insure consistency. A traditional medium that can be used for both thinning paints and glazing can be mixed with 1 part oil, 1 part damar varnish, and 1 part turpentine. If you are using odorless mineral spirits, you should eliminate the damar varnish, because it will not dissolve properly (1 or 2 parts oil to 1 part OMS). Replacing the linseed oil with sun-thickened will make a richer, faster drying medium. Using stand oil rather than linseed oil will also create a thicker and richer medium, although it will dry slower than a medium made with sun-thickened oil. Stand oil also gives the paint a glossier finish. (If you use the stand or sun-thickened oils, a thinner medium can also be made using 1 part of these thicker oils to 2 parts OMS.) Ralph Mayer's glazing medium - Ralph Mayer's, The Artist's Handbook of Materials and Techniques, includes several glazing recipes used by oil painters. A standard recommended glazing medium for an oil glaze painting is composed of 1 ounce stand oil, 1 ounce damar varnish, 5 ounces turpentine, and 15 drops of cobalt dryer. The cobalt dryer is added to accelerate the drying time of the slow drying stand oil, but if too much is added, the medium will coagulate. Ideally, a glaze should dry rapidly so artists can proceed with layering subsequent transparencies. The best glazes will dry overnight. Impasto wax and oil medium -- An impasto wax medium for oil paint can be made by gently and slowly melting 1 part bleached beeswax into 2 parts linseed, sun-thickened, or stand oil. Pour the oil in a coffee can and place this into a pot of hot water (basically, a double-boiler). When the oil is hot enough to melt the wax, place small pieces of beeswax into the oil until all the wax is melted. Stir thoroughly and allow to cool. If the mixture is too hard or too oily, reheat and add either more wax or oils as necessary. A drop or two of cobalt dryer can be added to help the medium dry more quickly. The final consistency should be similar to lard. Store oil painting mediums in glass jars with lids. Making homemade sun-thickened oil - The process of thickening oil is described in The Materials and Techniques of Painting, by Jonathan Stephenson. In the summer (or the tropics), pour about 1/2" - 1" thick linseed oil onto a flat, glass dish. The flat dish creates a large surface area for exposure to the sun and the air. Place the dish outside (on a ledge or roof) in an area that will be exposed to the maximum amount of sunlight. Thickening oil happens fastest in warm, sunny climates. Cover the dish with a slightly opened glass lid to allow for air flow. Stir the oil daily. After about a week or two, stir occasionally to prevent a skin from forming over the surface layer of the oil. Continue the process until the oil has thickened to a syrupy consistency. Impurities will settle to the bottom, so the oil on top can be poured off. Store in a glass jar with a lid. Commercial oil painting mediums Many art supply companies produce a variety of painting mediums for use with oil. In addition to traditional oil mediums (such as copal painting medium), many oil painting mediums are made with fast-drying alkyd resins which are soluble in odorless mineral spirits. Popular brands are Gamblin Paint Companies' Galkyd Medium #1 and Galkyd Lite#2, Daniel Smith's Painting Medium for Oils and Acrylics, Utrecht's Alkyd Glazing Medium, as well as Winsor Newton's Liquin. Alkyd based translucent impasto gels are also available, such as Gamblin's Galkyd gel, Utrecht's Flex Gel, and Winsor Newton's Oleopasto. Gamblin also produces a Cold Wax Medium for opaque impasto applications. Alkyd mediums are far less toxic than traditional oil mediums. They dry glossy and transparent. To extend the "open" time of fast drying alkyd mediums, small amounts of drying oil may be added. To prevent wrinkling, not more than 10% is recommended by Gamblin. (Gamblin has terrific technical support, by the way). Alkyds dry within 24 hours, so an adjustment to your approach to painting might be in order. However, an alkyd medium mixed with oil paint works well if you use a lot of transparencies and glazes, because layers can be applied overnight. Alkyd mediums, such as Galkyd or Liquin are thick (though not as thick as a gel). Galkyd Lite has been formulated as a thinner alkyd medium, although its open time is similar to Galkyd #1. Gamblin also makes Galkyd Slow Dry which dries slower than either Galkyd or Galkyd Lite. Solvents for oil paints The following is based on information provided by Gamblin Artist's Oil Colors. For further information consult the Gamblin oil painting solvent comparison chart. Turpentine -- Before the introduction of mineral spirits, turpentine was the only solvent available to oil painters. Unfortunately, this solvent is highly toxic and can get into the blood stream through skin contact. Made from distilled pine tree resin, turpentine is a strong solvent that dissolves damar varnish. It should only be used only with adequate ventilation. Mineral Spirits (paint thinner) is a petroleum based solvent. The toxicity of this solvent varies depending on the amount of aromatic compounds it contains. (Aromatic compounds increase the evaporation rate and produce noxious fumes). Mineral spirits will not dissolve damar varnish. This solvent is not recommended for use with artists' oils. Odorless mineral spirits (OMS) is the least toxic of the solvents. Some thinners sold in hardware stores are labeled odorless, but still contain aromatic compounds. Artists should use odorless thinners that have the lowest possible level of toxicity that do not produce noxious fumes. That is why it is best to purchase odorless thinners from art supply stores. Odorless mineral spirits is weak and does not dissolve damar varnish, but can be used in painting mediums that contain most stand and sun- thickened oils (Holbein sun-thickened oil will not properly dissolve in an odorless thinner). Odorless mineral spirits is also suitable for cleaning brushes and palettes. Nonetheless, this is still a toxic solvent and should be used with adequate ventilation. Oil varnishes Varnishes for oil paints provide a transparent layer over dried paint. Varnishes are primarily used to create an even gloss or matte finish over an oil painting and restores the original brilliance of the color. Traditional resins used for oil painting varnishes were derived from damar, a natural resin made from Indonesian fir trees. Oil paintings should be varnished after they are thoroughly dry. It is recommended that oil paintings dry for at least 6 months before applying a final varnish made with damar. Damar Varnish Preparation - Artists can make their own damar varnish by dissolving damar crystals into turpentine. Damar crystals can be purchased at art supply companies like Utrecht or Daniel Smith. The crystals are placed in a cheesecloth bag. (You can make a bag from a piece of cheesecloth tied at the top with a string. I've found pre-made cheesecloth bags at homebrewing supply stores). Suspend the bag into a measured amount of turpentine - usually about 1 part crystals to 3 parts turpentine by volume. The damar crystals do not dissolve properly in odorless turpentine. The regular hardware store gum spirits variety is best. Don't let the bag sink to the bottom. The turpentine will dissolve the crystals in a few days. Expect some of the crystals to remain undissolved. Today, many varnishes and painting mediums sold for use in oil painting are derived from alkyd resins. Alkyds were first used in the early part of this century in industrial paints (polyurethane and other floor paints are alkyd based -- artist quality alkyd paints are also available). Alkyds are very durable, but dry much more quickly than oils. Alkyd varnishes and mediums for artists' oils are soluble in odorless mineral spirits (unlike varnishes and mediums made with damar). Gesso made with alkyd resin is also available. Retouch varnish is used after the oil paint has dried to the touch to restore color brilliancy. Retouch varnish is weak and allows air to penetrate to the paint layer so oxidization can continue. Retouch varnish is available in art supply stores and is often made with an alkyd resin. Because of noxious fumes, all varnish preparation and application must be done in well-ventilated areas (outdoors is best if you can avoid insects). OTHER PAINTING MEDIA Oil paint sticks - Oil paint is now sold in a solid stick form, allowing the artist to draw with color onto a surface. Oil stick can be thinned with turpentine and can be easily incorporated into the process of oil painting. Oil sticks work much like oil pastel, but are richer in texture and color and, unlike oil pastel, will dry hard and permanent. After use, a skin will form on the end of of the stick. This can be shaved off prior to using the sticks again. Alkyds paints - Traditionally used as industrial and house paints, alkyd paints are soluble in turpentine or odorless mineral spirits, and can be used as an underpainting for oils or mixed direclty with oil paint. Alkyds share characteristics of both oil and acrylic paints; alkyds dry overnight, but can be blended and modeled like oil paints for several hours. They handle somewhat differently than artists oil paints, in part, because they have an even consistency regardless of the pigment used. Alkyd paints also cannot hold as much pigment as oil paint, and therefore, some alkyd colors are not as saturated. For information about alkyd painting mediums used with oil, click here. Water miscible paints - Paints that mix with both oil and water are now available. One commonly used brand is the Grumbacher "Max" paints. These paints handle somewhat differently than traditional oils but are less toxic (cleanup is with soap and water). Encaustics - Encaustics involve the mixture of dry pigments into molten beeswax. Artists melt the wax in small metal containers on a hot palette or hot plate. Pigments are added to the containers and the encaustic is applied to surfaces with brushes and other tools. Encaustics may have originated in ancient Egypt, and were used widely in ancient Greece. According to Ralph Mayer, the ancient Greeks also used a form of encaustics to add color to sculpture. This medium was rarely used during the renaissance, although the 18th century saw a revival of encaustics in mural painting. Encaustic painting, however, is primarily painted on the easel, and today many contemporary artists use encaustics in their work, such as Flag on Orange Fieldby Jasper Johns. Wax is compatible with oil paints and wax mediums are used in oils for impasto effects. (For additional recipes, see encaustics at Sinopiaonline) SUPPORTS Flexible - Light and convenient, paper and especially canvas are by far the most popular painting supports. Paper - Use only 100% rag (cotton) paper. Paper tape or staple (3" apart) the paper to a smooth, stiff, and rigid backing like masonite or wood. Canvas - Linen, like linseed oil, is derived from the flax plant. It is grayish in color and is considered best because of its durability and texture, but it is very expensive. Cotton Duck (sailcloth) is of high quality and comes in various grades and weights. Cotton duck (#12, weight: 11 4/10 oz.) is superior in quality. cotton duck #12 two grades of linen Rigid - Rigid supports are nice surfaces on which to paint because of their hard, flat surfaces. Their biggest drawback is their weight which can prohibit large scale painting. Masonite should be glued overnight (wood carpenters or stronger) to a wood frame using "C" clamps. This will keep the masonite rigid. Do not nail masonite to its wooden frame. The nails will show on the front of the surface and will rust. Quarter inch birch plywood panels should be similarly attached to a wood frame. Birch Panels - Birch plywood is a popular rigid support for painters because of its smooth surface and strength. It can also be obtained in larger sizes (4' x 8' sheets max.). Birch used for paintings should be 1/4" to 3/4" thick. Birch plywood is now available with a foam core which reduces the weight of this material. Masonite - Tempered or untempered masonite panels are also available in large sizes. Tempered masonite contains oily particles which make sanding the surface necessary in order to hold acrylic gesso, gesso sotile, or glue sizes. Tempered masonite is smoother, harder, retains its shape, and isn't damaged as easily as untempered. The main drawback of tempered masonite is its weight which can make it difficult to handle. Metals - (Copper, zinc, steel, aluminum). Oil painting can be done on various metal surfaces, including copper, zinc, and steel. Thin oil paint can create transparencies on metal surfaces. Acrylics may peel off polished metal surfaces or oxidize certain metals. Aluminum is a surface which works well for use with acrylics. The Solid Groundcompany produces hand-crafted panels for use with pastels and paints. The materials used in the panels are non acidic, non absorbent, and will not warp. The panels are extremely durable and chemically stable. PALETTES Palettes are the surfaces on which paint is arranged and mixed. Glass is the best palette surface because it is non-porous and can be easily cleaned. A homemade palette can be made by cutting a piece of tempered masonite and a piece of glass to the same size. The palette should be large enough to mix generous amounts of paint. Paint the surface of the masonite white (use acrylic gesso). After the gesso is dry, tape the glass to the masonite with masking tape around all four sides. Palettes can be cleaned with a razor scraper even if the paint has dried. Acrylic and oil painters should organize their palettes because it will make their painting more manageable and help achieve unity and color consistency in the work. Many painters use several palettes for different stages of the painting. A traditional modern palette looks like the Munsel or Itten color wheels with the addition of browns, black, and white. A small amount of each color is squeezed along the outside edge of the palette. Mixing is done in the center of the palette. Since each artist may have personal affinities toward certain pigments, not all palettes will look alike, but in general, palettes should be arranged according to the spectrum. This allows the painter to quickly and intuitively find colors on the palette. Artists who have a certain color scheme or effect in mind often limit the number of colors used on their palettes. Examples of palettes used by artists in western art can be found here. (Also see the palettes described in Faber Birren's,The History of Color in Painting for detailed analysis of palettes used by old master painters). Below is an example of a full palette: It is a challenge for acrylic painters to keep their paints from drying. Palettes can be purchased with lids to keep moisture from evaporating. Plant spray bottles also help to keep acrylics from drying. Separate plastic or glass containers can be used to store premixed paint. Disposable paper palettes are sometimes used by artists, but they can become messy and are often more trouble than they are worth. Notes on Palettes, Color Mixing, and Painting Techniques The transparency of a color effects its appearance. Glazes appear brighter than opaque layers of paint because light reflects through the glaze. Transparent colors do not have the same covering power as opaque paint. Painters can add portions of opaque color to transparent colors to increase their opacity. Simultaneous contrast is also important to consider in painting (read Joseph Albers, The Interaction of Color). Cool and warm colors suggest spatial relationships and complementary colors tend to intensify each other when used side by side. A solid understanding of color theory will give you better control of your painting. Because pigments come from the physical world, unlike the theoretical color of the color wheel, they may contain an undertone of another color. Ultramarine blue, for example, has a reddish undertone, making it a better blue to mix violets. Thalo blue, on the other hand, has a greenish undertone, making it the blue most suitable for mixing bluish greens. Mixing alizarin crimson with viridian (thalo green) will result in a blue-gray, because the bluish undertone present in both these colors becomes dominant, while the neutral created from the red (alizarin) and green (thalo) pigments result in a complementary color mixture of gray. With time, painters can quickly identify the color undertones present in tube colors. Certain tube colors, such as cadmium yellow can be easily mixed with other colors (reds and blues) to create oranges or greens. Cadmium red, on the other hand, creates a nice red orange, but makes a neutralized, dirty violet. This is why it is necessary to have both a cool and a warm red in order to create a range from orange to violet. Rose madder, crimson or naphthol red are examples of a cool reds. A similar thing happens with blue, although cobalt blue is very balanced and can create both blue-greens and blue-violets. Painters intentionally create undertones by adding trace amounts of color to create warmth or coolness. For example, black can be made warmer with the addition of brown or cooler with the addition of blue. White can be warmed with a tiny amount of yellow or yellow ochre or cooled with a very small amount of blue. VOCABULARY Alla prima - A painting technique used by the impressionists where a work was usually completed in one sitting with opaque layers of paint. (see Monet) Analogous colors - Related colors that lie adjacent on the color wheel such as blue, blue-violet, and violet. Analogous colors share the same primary color. Binder - An ingredient in paint which allows it to bind to a surface. A drying oil, such as linseed, is a binder. Blending - The process of mixing adjacent colors to eliminate abrupt divisions and create a smooth gradation from one color to the next. Because of their slow drying time, oil paints are ideal for blending colors. Chiaroscuro - An Italian term meaning, "light-dark", chiaroscuro refers to substantial changes of light in a painting that contribute to creating dramatic mood in a work. Chiaroscuro became popular in the baroque period. (see Carravaggio) Complement and Complementary Color - In color, any hue that is directly opposite on the color wheel. Dabbing - A painting technique used by impressionist painters where short strokes of paint are applied to the surface. Dabbing was done in layers and contributed to the flickering effect of impressionist works. (see Pisarro) Fresco - Fresco is a type of mural painting done on fresh lime plaster. Pigments are absorbed into the moist wall and become integrated into the surface. (see the Sistine Chapel ceiling) Gesso - Originally used in fresco painting, gesso referred to various mixtures of coarse and smooth plasters that were applied in layers in preparation for painting. Later, gesso (or gypsum) was added to rabbit skin glue to create gesso sotile (soft) grounds for panel painting. Today, the gesso most artists use is a blend of polymer emulsion and chalk. Glazing - Is the process of layering thin transparencies of paint. Glazes create luminous effects because light can pass through them and reflect back from the surface of the painting. In oil painting, most glazes are made from a combination of oil, damar varnish, solvent, and small amounts of paint. Today, many glaze mediums are made with alkyd-based resins to allow for both low toxicity and fast drying. In acrylics, glazes are made from a mixture of polymer media and small amounts of paint. (see Dutch still - life painting: Jan Davidsz. de Heem) Ground - The initial layer or surface of the painting which serves as a barrier between the canvas and the paint. Gesso is a type of white ground. Grounds can be textured, colorful, neutral, opaque, or transparent depending on the surface the artists wants to use. Before the impressionists, most paintings were done on a prepared ground, either imprimatura or toned. Impasto - Impasto is a thick application of paint. Rembrandt used impasto for highlights in a painting. This technique added both spatial and expressive qualities to his work. Later, painters like Van Gogh used impasto throughout the entire canvas. Today, acrylics are often used for impasto applications because they dry quickly and are easy to cleanup. For more about a recent Van Gogh exhibition, click here. Intensity - is created by the density of pigment in a particular paint. Intense colors are also known as saturated colors. Mixed colors tend to loose their intensity -- which is why most painters prefer to use pure tube colors rather than mixtures. (see Vermeer) Local color - The "actual" naturalistic color of an object -- as opposed to subjective color which is exaggerated or invented. Matte - A dull surface as opposed to a shiny surface. Opaque - An application of media that completely covers, for example, any underneath drawing or color. The opposite of transparent, light cannot pass through anything that is opaque. Pulling - A painting technique whereby paint is removed by a rag to expose areas beneath the outermost layer of paint. Pulling is also used to create marks on a surface. Shade - Colors which have been darkened by adding black. Scumbling - A technique where paint is lightly dragged over a a dry surface. Scumbling does not entirely cover the surface and allows underneath areas to show through. Tint - Colors which have been lightened by adding white. Value - In art, the relative darkness or lightness of tints, shades, and colors. White is the lightest, or the value with the highest key; black is the darkest, or the value with the lowest key. Varnish - A mixture of solvent and a resin, such as damar or alkyd. Varnishes are used to create an even gloss or matte finish over a surface which restores the original appearance of wet paint. In acrylics, pure gloss or matte medium serve as varnishes. Wash - A thinned paint made from a solvent (as in the case of oil paint) or water (as in the case of acrylics). Washes are different from glazes, because they are not made by adding more paint binder; such as linseed oil or acrylic polymer emulsion. In painting with oils or acrylics, washes should only be used in the initial blocking-in stages of the painting. Wet in wet - A technique of painting when wet (or oily) paint is applied onto a wet or oily surface. This is essential for blending colors. Painting is often done by applying paint directly onto undried surfaces so blending and color mixing can be done directly on the canvas rather than on the palette. STRETCHING CANVAS Cut the canvas large enough so that it can be stapled to the back side of the stretcher on all four sides. This means that an extra three or four inches of canvas on each of the four sides will be necessary. Place all staples on the back of the stretcher about three inches apart from each other. Use 5/16" staples with a staple gun. Begin by stapling the canvas at the center on one of the sides. Stretch the canvas directly across from this staple and place another staple on this side. Do the same for the other two sides of the canvas. After the first four staples are in place, pull the canvas straight up, then toward the corner. Staple from the center to the corner. Follow the same procedure diagonally across. Repeat until you have worked around the entire stretcher. It may be necessary to pull out staples and re-staple to get the canvas tight. On large canvases, temporary corner staples might be necessary, after the four center staples are in place, to help hold the canvas on the stretcher. Excess canvas should be cut from the back. The edges of the stretched canvas should be smooth and gessoed along with the front of the canvas. Corners should be saved for last and are neatest when folded like the corners of sheets on a bed. Smooth corners are easier to frame.