How to determine the condition of paintings on canvas, board or linen like an expert

This article will explain common condition issues found in paintings on canvas, board or linen. It will give you the tools to determine if common condition issues are present in the paintings that you own.

Keep in mind that if you discover condition issues, they will not necessarily hurt the sales value of your artwork. Some condition issues are inherent to the materials used to create the piece, and their presence can help confirm authenticity. Should an expert determine that restoration prior to a sale would increase the resale value of the piece, that same expert should be able to recommend a restorer who can perform the work.

It is best to remove a painting from the frame when looking for condition issues because the frame can conceal parts of the work. However, if you are not comfortable with the idea, do not remove the piece from the frame.

When handling the work, make sure your hands are clean and dry, or wear clean gloves. This step is vital because the oils from your fingertips can cause damage to the artwork.

Many condition issues can be detected with the naked eye, but you should also examine the painting using a light source. Note that certain issues may require a magnifying glass or a black light to detect.

Once you’ve set up the painting for examination, you should look for the following issues:

  • Tears or Rips
  • Paint Loss
  • Craquelure
  • Inpainting, Overpainting and Retouching
  • Water Damage
  • Varnish Discoloration
  • Fading or Overcleaning
  • Surface Dirt
  • Re-lining
  • Sagging or Looseness on Its Stretchers
  • Frame Damage

Tears or Rips
Examine the front of the work. Are there any tears or rips in the canvas? Look at the back of the painting. Are there are any patches? Canvas patches can indicate that a tear has been repaired.

Paint Loss
Look closely at the entire surface to see if there is any paint loss. If you have a magnifying glass, use it. Examine the surface in raking light, which is light that falls across the surface at an angle. Viewing the work in raking light can help you determine if there are cracks in the surface of the paint or areas of loss. Related issues include cleavage (separation between the paint and ground layers), flaking and lifting.

Craquelure is a very common condition issue. The term describes a network of fine fracture lines in a paint layer. It often resembles spider web­-like cracks, but it can manifest in several different ways. Craquelure may only be present in certain areas of the surface, and the size of the cracks can vary from a centimeter to a few inches. It often occurs naturally as a painting ages, but it can also be caused by an impact to the canvas, by rolling or folding the unstretched canvas, and by exposure to humidity or other environmental influences. Craquelure can lead to flaking and lifting and can indicate poor adhesion between the paint layer, varnish layer and support. To look for craquelure, examine the surface in raking light.

Inpainting, Overpainting and Retouching
Inpainting or retouching is the introduction of new paint into small areas of loss in order to restore continuity and conceal damage. Overpainting is an application of new paint that completely covers the old surface. The results of these conservation techniques are difficult to detect. Look for areas where the paint color is slightly different. Inconsistent brush strokes or areas where the paint is thicker can also be signs of restoration. Often, inpainting is used to conceal a tear in a canvas that has been patched on the reverse. Sometimes, areas that have been restored can be detected because condition issues present in other parts of the canvas are absent. If you have a black light or ultraviolet light available, take your painting to a dark room and examine the surface under the black light to see if any areas of the paint fluoresce differently. Older paint will look different from new paint under black light; new paint will usually look darker.

Water Damage
Examine the back of the work. Are there any discolored areas that might indicate the artwork came into contact with water or another liquid? Moisture exposure can cause the canvas and the wooden stretcher bars to expand and contract or warp, which can disturb the paint layer and cause lifting.

Varnish Discoloration
A final protective coating of varnish is often applied to a painting in order to protect and preserve the paint layer. Varnish can discolor, darken and deteriorate with age, affecting the overall appearance of a painting. Varnish often yellows with age and becomes brittle.

Fading or Overcleaning
Fading is a gradual loss of color or intensity. This can be caused by exposure to sunlight, or it can be inherent to the type of paint. Fading can also result from overcleaning.

Surface Dirt
If a painting is not kept under glass, a layer of surface dirt will naturally accumulate on the surface as time passes. This dirt often consists of dust, soot, smoke and natural particles found in the environment. To determine if your painting is dirty, closely examine the surface. Does it appear dark or soiled? Check the frame to see if a layer of dirt has accumulated on the top edge or along the lower interior lip. Then, put on clean white cotton gloves, or take the corner of a clean piece of paper towel, and press it gently on the surface of the painting near the edge. If the material is darkened when you lift if off, your painting may need to be cleaned. Do not attempt to clean the work yourself.
Example of surface dirt

Re­-lining is the process of reinforcing the canvas by applying a second canvas or material lining to the back of the original and securing it with pressure and an adhesive, usually wax or glue. Until the 1970s, re-­lining was a common restoration technique used to fix tears, unstable paint and deteriorating canvases. Because the adhesive used in this process eventually can seep into the original work and cause adverse effects, re­-lining has become less common today. To determine if a canvas has been re-­lined, turn the painting over and look carefully at its edges. Does it look like another piece of canvas has been sandwiched to the back of the original canvas? There may be glue or wax residue along the edges. The back of a re-­lined canvas may also appear new.

Sagging or Looseness on Its Stretchers
The fibers in stretched canvas often lose their tautness over time, causing the material to sag on the wooden frame. When you gently shake the painting, does the canvas move? Does the canvas sag or bend? Examine the canvas in raking light. A restorer can easily tighten a canvas that has become loose on its frame.

Frame Damage
Is the frame stable? Are there chips? Has the gilding worn away or flaked off? Frames are decorative and also serve to protect the edges and surface of a painting from damage. Because frames can be replaced, experts generally do not consider the condition of most frames when valuing an artwork.

Past Repairs or Conservation
If your painting has been conserved or restored, do you have documentation of the treatment? This paperwork should accompany the painting so that future owners know what treatments it has received and when the services were completed.