Brush sizes for oil painting depend on the area you need to cover.
Every artist who works with oil paints should know properly prime a cotton or linen canvas. Preparing the material with gesso prevents the oil in the paint from migrating into the canvas and creates a smooth surface on which to paint. While most mounted canvasses and canvas boards sold today are pre-primed, further treatment can provide a smoother painting surface. Creating an oil painting all the way from raw canvas to finished art piece may also offer a welcome new challenge for an experienced artist.
Instructions
1. Assemble your supplies. Gesso dries very quickly, so it is necessary to be prepared. You'll need a running water supply and plenty of paper towels nearby (cloth rags are fine, too). You want to work on a flat surface that is protected by newspaper for easy cleanup.
2. Stir the gesso in its container. Pour or scoop out roughly an inch or so of your gesso into the plastic cup. Since gesso--being plastic and water soluble--dries quickly, only pour out as much as you need. Then, close the container immediately. It is not advisable to pour used gesso back into the original container.
3. Add a small amount of water to the gesso in the cup, and mix thoroughly. Wipe off the stirrer immediately.
4. Waiting for the gesso to dry thoroughly between coats is sometimes the most challenging part of prepping a canvas.
Wet the nylon bristle brush under running water. Squeeze out the excess water, and dry the brush off with paper towels until the bristles are just moist. This prevents the gesso from sticking to the bristles. It also facilitates clean up afterward.
Dip your brush about 1/2-inch deep into the gesso mixture. Wipe the bristles off on the side of the cup to remove any excess gesso. Using short strokes, cover the canvas. You will need to use some force when brushing on the gesso.
Finish the first coat quickly by going over the entire canvas with long strokes, brushing in one direction (either up and down or side to side). You want to avoid leaving thicker lines of gesso, but you should not attempt to brush out the gesso once it begins to set up.
Wash your brush with soap and water immediately after use, otherwise the brush will be unusable in the future. Lay the cleaned brush flat with the bristles extending over the side of the table until completely dry.
5. Allow the canvas to dry for at least one hour, longer if temperatures are very cold or if it is very humid. When the gesso has dried thoroughly, sand the surface with the 120-grit sandpaper. Clean off any residue with a paper towel.
6. Apply a second coat of gesso. Although it is not necessary to dilute this application of gesso with water, you may if you wish. Apply the second coat employing broad strokes applied perpendicular to the direction of the first coat.
7. Sand the canvas once more after drying to remove any residue. The canvas should be smooth to the touch. If it is not as smooth as you would like, apply another coat of gesso following the previous steps. The final coat should be allowed to dry overnight.
