Watch for water that has collected between the stretcher and the reverse of the painting. If a lot of water has accumulated, tip the painting so that the water can run out and away from the painting (i.e., tip the painting bottom face upwards and the top reverse downwards, so the water runs off the stretcher and not into the canvas).
Carefully blot out remaining water with toweling, without putting pressure on the reverse of the canvas. If avoiding the reverse of the canvas is not possible, place the painting face up and lift each edge sufficiently to allow you to catch the water as it drains from between the stretcher and canvas with toweling. Start and finish with the lower edge, You may want to consider slipping paper towels between the stretcher and painting all along the wet edges in contact with the wood of the stretcher. This will allow the colored material that is extracted from the wood to be absorbed into the toweling rather than stain the reverse of the painting. This is particularly important with paintings with exposed raw canvas or exposed ground. The paper towels must be changed frequently. While this will not stop the migration of colored material into the canvas, it should reduce the staining significantly.
Excess moisture can be gently blotted from the reverse of the painting. Do not blot the surface, as this could disrupt fragile paint.
Never try to dry a painting with a hair dryer. This will cause uneven drying and local overheating. The stresses generated could cause additional damage.
Generally, don’t try to remove debris from the reverse of the canvas while it is still wet. This is better done after the painting has dried.
If there is wet debris on the surface of the painting and the painting itself is still wet, you may want to consider carefully rinsing the offending material off. It is often better to remove this material before it dries on the surface. This is not anything you would do on paintings with water-soluble media or with lifting or flaking paint or other serious damage. If you decide to rinse the paint surface, do it somewhere where the runoff will not make more of a mess than you are already facing. A pump sprayer, the type used for spraying insecticides (please don’t use one that has been used with insecticide previously), may be your best choice. These have a long wand on the end of a flexible hose and a tip that can be adjusted to provide a fine fan-like spray pattern. The painting would be stood vertically, face-out on blocks, and the spray worked gently from the top down, pushing material off and down.
If possible, dry paintings flat, face-up. If space does not allow for horizontal drying, stand the paintings bottom-end (wettest edge) on top, leaning face-in against a wall or something structural. Place a cloth or foam pad between the top edge and the wall and blocks below. Periodically rotate the painting 180 degrees, so the damp area on the bottom goes to the top, allowing more even evaporation. As always, put padding between the floor and the painting—Ethafoam blocks are great for this. If the floor is dirty, polyethylene sheeting covered with paper would make a suitable surface.
To allow a painting to dry face-up horizontally, block the painting four to eight inches above the surface that is supporting it, so air can circulate behind the painting.
If you notice flakes of paint lifting, tenting, or beginning to fall away, the endangered area should be faced. A facing of thin tissue will hold the paint flakes in position for subsequent reattachment and will stabilize vulnerable areas. Any thin tissue will do, from Japanese tissue all the way to toilet paper or Kleenex.
Generally, a reversible adhesive is used to hold the tissue and at-risk paint in place. If the surface of the painting is stable to paint thinner (mineral spirits) Golden MSA gloss varnish or Gamvar (Regalrez) varnish can be used to secure the tissue. Once the tissue is in place and has conformed to the surface, the varnish is gently brushed onto the surface of the tissue. Don’t move the tissue or crush the paint below while applying the varnish. If the surface is not stable to mineral spirits, a water-based adhesive can be used: commercial wallpaper paste, wheat starch paste, or methylcellulose will work. Do not use any water-based material that doesn’t re-dissolve in water after it has dried. This would include emulsion varnishes, acrylic painting medium, and emulsion glues.
If using fans to help dry the painting, try to have the air flow more on the reverse of the painting and as gently and uniformly as possible. Having the air in the entire room circulating is better than having a blast from the fan(s) directed at a painting.
Slow drying is better than fast drying. If using heaters to speed the drying, don’t overheat the room or have the heaters pointing directly at a painting. The paintings have been through enough; we don’t want to cook them. Likewise, if using dehumidifiers, do not over-dry the air.
Once the painting is dry, debris on the surface can be gently loosened and brushed off with a soft brush. Brush towards the nozzle of a HEPA vacuum to catch the material, and wear respiratory protection—we don’t know what’s gotten into that residue. Debris on the reverse can be carefully vacuumed up using a slightly stiffer brush.
Consider carefully before wrapping a painting in plastic after it appears to be dry. There is likely residual moisture in the stretcher and other areas you might not be aware of. Wrapping a painting in plastic at this point could lead to a fresh mold outbreak.
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