Artists may use oil paint directly from the tube and never use another product until it is time to clean the brush.
That is down and dirty painting, and is refreshing and spontaneous.
However, a good part of the time the artist will mix either a solvent or a medium to alter the texture of the paint.
The artist may want a thin, dilute concentration to underpaint and requires that it dry quickly.
Conversely, glazing parts of his work in the final stages demands a dilution that dries slowly to avoid curing problems.
There are many additives for oil paints available to the modern artist, and they can be multipurpose or used for specific tasks. The student can be carried away with all the products on the market, each one touting its unique characteristics and superior quality.
The fact is that a beginning artist needs only two additions to his oil paints. A solvent and a medium are the two items that will go in the painter’s tabouret along with his paints.
As his skill increases, he may wish to try other styles and methods by including new items. When the budget allows, many other products can be useful and add another dimension to the student’s work.
Oil Paint Solvents
Artists have used turpentine for hundreds of years. It is an organic product, derived from tree resin. Regardless of its organic nature, it is easily absorbed through the skin, and as it dries releases noxious vapors. Both inhalation and absorption can be dangerous, so this product should be used cautiously with adequate ventilation and minimal physical contact.
This is not a time to skimp on product. The hardware store variety of turpentine is inexpensive because it is less refined than the artist quality product. An artist should not use this type of solvent in painting, as it may contain impurities that could have an adverse affect on their painting. A truly starving artist can get away with using hardware store turpentine to clean brushes, but that is about the extent of it. It may also be sold under the names spirit of turpentine, distilled turpentine, or rectified turpentine, as well as several others.
Mineral spirits is a petroleum-based product that is also harmful if inhaled extensively. This product is good for the person who is allergic to turpentine, and it is less costly. Odorless mineral spirits or white spirits is not as strong as mineral spirits, but is less noxious. It is more costly than mineral spirits, as it has been refined to remove odors. Brand names include Thin-ex, Gamsol and Turpenoid.
Oil Paint Mediums
A number of mediums are used in oil painting. These products differ in drying time and have varying characteristics that are used in diverse applications or styles of painting. Some products are translucent, while others may be opaque. Other products speed up drying time and others prolong drying. There is matte finish, satin finish and high gloss medium. The student should learn the differences, so he can make an informed decision regarding his purchases and the manner in which he uses them.
Linseed oil is derived from the flax plant seeds. This all-purpose oil is very popular and dries in three to five days. It is light yellow in color, and may darken with age. Cold-pressed linseed oil is a higher quality product that dries more quickly than refined linseed oil.
Stand oil is a more processed form of linseed oil that is thicker in consistency and is much slower in its drying time. Although it may be dry to the touch in a week, months may pass before it has dried completely. When mixed with turpentine or other solvent, it is useful as a glaze. Stand oil has fewer tendencies to darken or yellow, so is a better choice for blending with white and pale colors.
Poppyseed oil is a pale oil that is a good choice for the lightest tones in a painting, as it ages well and does not darken. Since it dries slowly, it is not recommended for use in the beginning stages of a painting. It is suited for final layers and wet in wet technique.
Walnut oil is thinner oil that dries in four to five days and is suitable for white and light colors. It is more costly than some other mediums and must be properly stored to prevent it from becoming rancid.
Other oils available to the artist are Safflower oil and Sunflower oil. These oils are not as widely used, but are alternatives a student may consider.
Boiled oils tend to darken or yellow with age. They generally have been modified to provide more rapid drying. These oils are typically used in the initial stages of painting where color changes will not affect the painting and quick drying is important.
Drying Times and Color Changes
With any oil, the artist should be aware of drying time and color changes. Taking the time to do testing of products one considers adding to the paint box can save heartache later. A glorious landscape with a beautiful azure blue sky that slowly turns green to match the meadow is good reason for experimenting with a medium before adding it to the tabouret.
Using a medium that dries too slowly early in a painting can result in the paint cracking as it dries. This may not be evident for several months, as an oil painting may take up to six months to cure. A student must practice fat over lean in painting. This is not just an old saying, but expresses the physics involved in the use of the products in the artist’s paint box. Ignoring the physics of art can result in a ruined painting and a waste of the artist’s time.
The joy of paint-flinging is every artist’s ideal. Being in the moment when everything is working is ultimately satisfying. However, it is important for the student to learn and understand the theory behind his painting. This may be the boring part of an artist’s study, but a very necessary element in a student’s education.