Paintings are images created by applying coloured mediums to a support.
They can be made with a range of pigments combined with oil, acrylic, or natural ochres and applied to a variety of supports including paper, canvas, wood, metal and walls. Paintings consist of multiple layers of different materials, built up from canvas or hard support, one or more ground layers, paint layers and varnish layers.
Torn canvas of an oil painting. Photo: courtesy of Art Conservation Framers
Causes of deterioration
The effect of visible and ultraviolet (UV) light can cause fading, yellowing, discolouration and darkening to a painting’s surface. Light can also cause chemical changes such as embrittlement and an increased rate of deterioration, particularly in exposed areas of canvas.
Temperature can increase the rate of deterioration, and cause increased sensitivity in synthetic polymer based paints.
Painting supports are particularly vulnerable to humidity, since fluctuations can cause the support to expand and contract and cause cracking in the overlying paint layers.
The easiest way to reduce these effects is to be careful where to hang artworks and what lighting to use: Avoid exterior walls, direct sunlight or lights containing UV (e.g. fluorescent lighting), and secure a backing board to the reverse of the frame to buffer from any sudden changes.
Paintings contain a number of organic materials that are sensitive to insect attack such as borers and beetles. Insect droppings are acidic and can additional damage to the surface.
Signs of insect damage include exit holes, frass, and the presence of insects themselves, either alive or dead.
Good housekeeping and regular inspections will assist with minimising insect damage, as does glazing artwork.
Dust and dirt
Deposits of dust and dirt scratch the painting surface, along with air pollution that can damage the painted surfaces including those of the frame.
Keep paintings away from open or gas fires, heating and cooling ducts, tobacco smoke, and food preparation areas. Correct glazing of the painting reduces the risk of damage.
Paintings are prone to damage by accidents and poor handling. Stretched canvas is sensitive to vibration, which can cause paint flaking and loss.
Make sure that your painting is stretched and framed correctly and fitted with a safe and appropriate hanging system. Avoid hanging artwork in high traffic areas such as hallways.
Obtain specialist advice when transporting or storing paintings.
Deterioration can affect any or all of the layers in a painting.
Not all damage can be undone, though typical treatments include surface cleaning; removal and replacement of deteriorated varnish layers; removal of old and discoloured overpaint; consolidation of flaking or powdering paint layers; removal of mould and blanching; tear repair; flattening, strip and full lining; stretching or re-stretching canvases; filling and inpainting areas of loss; and refitting paintings into frames with secure padding and hanging devices, glazing and backing boards.
Paintings conservators are qualified professionals who work in a range of public and private institutions. They ensure that paintings in their care are preserved in a stable condition, and undertake treatments for the long-term preservation of the work.
A thorough understanding of the physical and chemical properties of artists’ materials and intent, the art historical context, and the significance of the painting are needed before commencing any treatment.
Painting conservators collaborates with art historians and scientists to examine the structure of individual paintings, research artists’ materials and methods and the techniques and materials needed for conservation treatment. This interdisciplinary approach provides invaluable information about the way a painting would have originally appeared, and helps reveal an artist’s unique techniques in constructing the work.
The paintings conservator studies a painting extensively using a combination of technical tools including microscopes, X-ray equipment and infra-red cameras. Such technical research is vital to current conservation work as it guides treatment, assists in attribution and helps distinguish original layers of paint from later additions.
Paintings conservators are also able to assist with advice regarding painting care, mounting and display, and provision of documentation (condition reports, treatment assessments, treatment reports, photography).
Video: Filmed over 18 months, this is the story behind the restoration of Mark Rothko’s ‘Black on Maroon’, via Tate.
AICCM has a Special Interest Group for those interested in paintings conservation. Join this group, contribute to its activities, or speak to a specialist conservator.