As for any artwork, caring for fine art paintings requires a certain understanding and attention to detail. This article addresses some important characteristics of the medium and offers guidance to help keep your paintings in good condition and safe for future generations. While acrylic and oil are not the only techniques of painting, they are the most common and thus the focus of this article. The most prevalent causes of damage to both acrylic and oil paintings are inappropriate storage, displaying works in areas with fluctuating temperatures, over exposure to light, fluctuating humidity levels and airborne dust and dirt. These dangers should be kept in mind whenever you hang or store your paintings.
Whether you are hanging your paintings for display or storing them sudden environmental changes should be kept to a minimum. The following are commonly acknowledged as acceptable environments for paintings: during Winter 18 to 21ºC (65 to 70 ºF) with relative humidity of 40 to 45%, during Summer 21 to 24ºC (70 to 75 ºF) with relative humidity of 45 to 55%.
Oil painting, which became prevalent in the 1400s, consists of pigments suspended in oil — the carrier. Today, the most commonly used oil is cold-pressed linseed oil known for its durability, the fact that it is quick drying and because it yellows less than other oils. However, other oils are still used to achieve different effects of viscosity or consistency; this is one benefit of using oil instead of water as a carrier.
There are a few points to consider when it comes to care and maintenance:
• Oil paintings yellow over time, this should be considered an unavoidable and perhaps even an attractive trait
• Oil paintings are more likely to crack than other kinds of paint
• Oil paintings can flake due to the hardness of the material
• Oil paintings can take up to a year to fully dry; those which are not fully dried are most sensitive to light or dark
• A coat of varnish can be applied as a protectant by a professional only after the painting has fully dried.
If properly cared for, oil paintings can last for centuries. Like all paintings your works in oil should be kept clean and free of dust but deep cleaning and other interventions should always be left to a professional.
Acrylic paint is an emulsion that consists of an acrylic polymer resin suspended in water. It is a quick-dry paint. As the medium is a comparatively recent addition to the history of painting (it became available on the market in the 1950s), the long term aging effects and the way in which degradation occurs are yet to be fully understood. As the Smithsonian Museum Conservation Institute (MCI) has outlined, preventative care, rather than restorative care, is currently the most important type of maintenance. It is now common knowledge that the surface of an acrylic painting, the acrylic film, is more susceptible to the buildup and retention of dust and dirt particles than the surface of an oil painting.
Oil paintings continue to dry after they are applied to canvas. The oil molecules expand as they are exposed to oxygen, hardening the paint surface and eventually cracking. Although acrylic paintings dry faster than oil paintings, oil paintings have a harder surface once they dry. The key reason that the surface of acrylic paintings remains softer and more flexible at room temperature is because of their chemical makeup. As this emulsion dries the flexibility in the paint remains. The flexibility of the paint film make acrylic paintings less susceptible to cracks. Acrylic paints are able to be applied to a wider variety of surfaces and able to hold different mediums that are used as additional layers (unlike oil painting which tends to only support more layers of oil paint). A frame with a protective glass is a good preventative solution for acrylics. Of course, the glass should never be in contact with the surface of the canvas (see diagram below).
There are several key considerations in the upkeep of acrylic paintings:
• Additives (stabilizers, preservatives etc.) present in the acrylic emulsion can make a painting more light-sensitive
• Paper backings are also light sensitive and can become brittle easily
• Raking or ambient light should be used to display paintings and these light sources should have UV filters and bulbs (ideally xenon, not halogen) which are a brightness of 200 lux
• If you do not frame your acrylic painting or use a glass protectant avoid touching it. Because of the softness of acrylic polymer films, even a fingerprint can cause permanent damage to the surface of the work and will be especially visible on monochromatic abstract paintings
In closing, acrylic paintings are more susceptible to dust than oil paintings because of their soft films. They are created with a relatively new emulsion and methods of conservation are still being discovered as the material ages. Protective framing and glazing is a viable way to prevent dust buildup. Varnishing is not a beneficial protectant. Preventive care is what is most needed when it comes to taking care of acrylic paintings.
Perhaps Obvious, but Still Worth Mentioning
- • Paintings should be stored at room temperature but a more serious threat than temperature is humidity and exposure to airborne dust and dirt
- • Do not clean a painting by yourself. Always seek professional help and remember that conservators strive to minimize interventions (hands on restorative work) because many restorative treatments for paintings can never be reversed
- • Never hang near ventilation systems or close to a space heater
- • If you feel your painting needs surface dusting, never use a conventional feather duster. It risks scratching the surface of the painting. A soft brush, such as an artist’s paintbrush that is made of goat’s hair is adequate. Badger and sable hair brushes also work
- • If works are not on display: Keep exposed canvas/linen, paper backs away from any protrusions; stack the works upright with rigid dividers (thick cardboard for example) separating the paintings. Unless you have a set of shelves whose back is larger than that of the back of the painting, stack the paintings against a wall face to face
- • If works are not on display: keep them stored in a room with a temperature that you would be comfortable living in (~20 degrees Celsius, although acrylics should be stored at slightly less than room temperature so that the paint film is less likely to soften) and a climate (40-60% RH) that is not susceptible to sudden drastic environmental changes
Components of a Framed Painting
This article is not intended as a complete guide but rather as a set of integral rules to help collectors keep their paintings in excellent condition.