Stabilizing Wet Paintings

From Wiki

Introduction

The following tips are suggestions from conservators, but please realize that every painting and circumstance is different, and that these are general guidelines. A conservator may choose very different treatment options from those presented below upon seeing the painting’s condition. On the whole, conservators have less experience treating art that has been damaged by salt or brackish water as opposed to fresh, and we are still sorting out the differences ourselves.

If time and resources allow, you are always better off consulting with a conservator rather than trying to treat a painting yourself. Of course the volume of damaged work caused by Hurricane Sandy will require prompt, proper, and mindful action by non-professionals in order to minimize damage even in extreme circumstances.

Remember to stay calm and mindful during recovery. Rushing and being anxious will only make things more difficult and lead to mistakes. Recovery is very challenging and the process will be more successful when approached with calm and patience.

Be sure to document everything—absolutely everything. Photos, dictated and written notes, and videos will all be crucial in the aftermath. These are necessary for insurance claims, future allocation of resources, and even documenting the full scope of the disaster.

Also, don’t throw anything away yet. Very rarely is something a total loss. Often we hear of entirely salvageable works having been discarded in the immediate aftermath of a disaster.

Facts about paintings

Paintings are composite objects – support layer, glue and/or priming layer, design layers, and varnishes.

  • Canvas and wooden components expand and contract
  • A variety of media can be present on any given artwork
  • Paintings are vulnerable to punctures and tears
  • Hanging hardware and wires can be handling issues
  • Frames can be simple or ornately carved and gilded


What to expect when paintings get wet

  • Canvas supports can become tensioned
  • Wooden supports can warp and split
  • Composite objects may delaminate
  • Larger paintings will be very heavy when wet
  • Varnishes will be sensitive to abrasion
  • Glue and priming layers will be unstable
  • Mold can grow
  • Damp environment can be just as damaging

Dealing with Wet Contemporary Paintings: Tips for Artists—Water Damage to Paintings

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.

Drying paintings

  • If surface is insecure, lay painting face up.
  • Air dry slowly and controlled (tenting and block up from table)
  • If paint is stable, place face down on clean table and gently blot the back.
  • Blotter strips can be gently inserted between stretcher bars and canvas
  • Lay painting face up on table and block up off from table surface.

Dealing with Wet Contemporary Paintings: Tips for Artists—Wet Paintings: Structural Issues

Never remove a wet painting from its stretcher bars. The stretcher bars are keeping the canvas from shrinking. The painting is apt to generate enormous tension in the wet canvas—somewhat less so with salt or brackish water—as the fibers swell with the water. If the tacks or staples seem to be pulling, add additional staples to the tacking margin or reverse.

If the stretcher buckles or even breaks under the tension of the soaked canvas, this must be dealt with promptly. If the painting is warped (two diagonal corners up and two down) try to shore up the stretcher. Heavy wood or metal plates can be screwed through onto the reverse of the stretcher. A 2×4 or other dimensional lumber piece can be added to the sides or reverse to strengthen the stretcher. Be very careful to not let the screws being used pierce the stretcher and pass into the painting. Best practice is to hold a small metal plate between the painting and stretcher so if the screw goes through the stretcher, it hits the plate rather than the canvas; then you can just back the screw out to a safe depth.

On larger paintings or paintings with very narrow or flimsy stretchers it may be necessary to add cross-bars or cross-braces to keep the longer members of the stretcher from bowing inwards under the enormous tension in the canvas.

There are two options: If the stretcher hasn’t bowed but you are concerned that it might, simply screw a cross-bar onto the reverse of the stretcher, securing it with screws through the cross-bar and into the stretcher. Again, be very careful about the depth of the screws and not driving them into the painting itself.

If the stretcher has already bowed and you have the materials, equipment, and time, you can make a cross-bar. Cut a board no thicker than the existing stretcher to the inner dimension of stretcher before it bowed. You can get this dimension by measuring the inner dimension at the parallel edges. Ideally, cut curves on two ends of the bar diagonally across from each other. Place the new cross-bar member into the space between the two bowed stretcher bars but don’t let the cross bar touch the reverse of the canvas. Because of the bowing, the cross-bar will not fit, so place it on a diagonal with the curved cuts on the ends against the bowed stretcher bars. Slowly, perhaps over hours, twist the cross-bar into a successively more and more vertical orientation. The new cross-bar will need to be secured to the stretcher after each adjustment. A small block of wood can be screwed into both the cross-bar and stretcher on each end of the cross-bar.

If a stretcher breaks, try to work the stretcher back into place. Metal plates or bars can be attached to each side of the break with screws. If necessary, the stretcher can be pulled back into position with clamps compressing the caved-in stretcher to an auxiliary bar along the entire edge.

Dealing with Wet Contemporary Paintings: Tips for Artists—Frames

Dealing with paintings in their frames poses a difficult set of tradeoffs. First remove all backing materials—paper, cardboard, Foam Core Board, or plastics.

Remove paper or cardboard backings from the reverse of the painting. They have done their job, and their continued presence will just complicate matters. This should be done as promptly as possible. If there are labels, save them, noting which painting they were from (i.e., document everything!). Don’t forget that labels are part of the painting’s history and establish its provenance.

If the frame is a strip frame, it is only holding moisture along the tacking margins and it should be removed eventually, but this is probably not the highest priority task. It is also likely that the nails holding the strip frame will rust, potentially causing stains in the tacking margins.

A shadow-box frame, without glazing, will provide structural support, so you may want to consider leaving it in place if it doesn’t restrict airflow to the reverse, and you can blot out any moisture between the edge of the painting and the frame.

If a frame is falling apart (like the gesso softening and smearing), it is best to remove the painting from the frame as quickly as possible.

If the frame is strong and has a traditional rabbet against which the painting is pressing, you will have to make a judgment call. The frame can hold water against the very edge of the surface and along the tacking margins, so for this reason it is best to remove the painting from the frame. However, if the canvas has shrunk and the stretcher is not sufficiently strong, leaving the painting in the frame will help restrain the stretcher and prevent torqueing.

Deciding which action to take should be based on the stretcher type and thickness, the construction of the corners, and how securely the painting is held into the frame. Raw canvas or exposed ground along the edges are more apt to be stained from contact with the wood of the frame, so in these cases it is probably best to remove the frame from the painting.

Packing damp/wet paintings

(Hutchins and Roberts. First Aid for Art: Essential Salvage Techniques, Hard Press Edition, Lenox, MA. Page 45)

  • Wrap painting in glassine, clean newsprint, or clean plastic sheeting
  • Sandwich between two pieces of cardboard, slightly larger than frame
  • Tape cardboard edges together
  • Write “Face” on front of package with brief description

Dealing with Wet Contemporary Paintings: Tips for Artists—Mold and Paintings

Never wrap a wet painting in plastic, as this will promote mold growth. Also, the surface may be quite fragile and nothing should come in contact with the surface until it has been thoroughly dried and inspected.

Paintings wrapped in plastic should be removed from the plastic to prevent mold growth if they were in a damp environment, even if there is no overt indication of water damage once they are removed to a safe and dry environment.

If the painting is glazed, the frame should be removed as soon as possible. The microenvironment between the glass or acrylic and the surface of the painting could be very damaging and could lead to sudden mold growth on the surface of the painting, a severe problem that is very difficult to reverse. The glazing will also impede the drying of the painting.

Surfaces (other than art) can be treated with a 10% solution chlorine bleach (one cup of bleach (e.g. Clorox) to one gallon of water).

For mold on the actual artwork, the reverse surface can be lightly misted with 70% alcohol in water. Commercial rubbing alcohol is perfect for this as it normally comes already diluted to 70%. Oddly, pure isopropyl alcohol is not as good as the 70% mixture at killing mold, so, in this case, more is not better. The alcohol and water will desiccate and often kill most active mold. The goal is to just barely dampen the surface. A simple hand-pump sprayer adjusted to a very fine mist is perfect for this. Try to avoid spattering.

If small colonies of mold are growing on the surface of a painting, you can consider lightly dabbing the surface with a cotton swab dampened with the alcohol/water mixture. However, be aware that this is a potent solvent for artist materials and could also damage or alter the paint surface. Testing on an inconspicuous spot first is always a good practice.

When dry, the surface should be vacuumed carefully with a HEPA filtered vacuum. Even when dead, mold can cause potentially dangerous allergic reactions and the HEPA filter will trap the bits of mold from being spewed into the air. It will also trap mold spores so you won’t be spreading them around. Mold on the face of a painting should be removed with a soft brush. Brush the mold up into your vacuum’s nozzle, held just above the surface of the painting.

Salvage priorities

  • Most highly valued (curatorial and monetary)
  • Least damaged
  • Slightly damaged
  • Severely damaged

Specific Procedures

November 11, 2012, 5:50 p.m.

Masonite panel needs to be re-glued to a floating frame. The oil painting is fine. What type of glue do you suggest, I heard PVA glue was good. The painting measures 12″ by 24″. Thank you.

Posted by Neddi Heller November 12, 2012, 11:05 a.m.

Assuming that this is flood damage, make sure the Masonite is completely dry before re-gluing.

When you say floating frame, I’m not sure if you mean a frame with an L profile; the sides project forward surrounding the painting and the base of the L is glued to the reverse of the painting? Or, are you just referring to a frame work that attaches just to the reverse of the panel.

PVA emulsion is a good choice for the adhesive.

If the painting is wet, your first, best choice is to consult a conservator. If you wish to proceed, we want to dry the painting slowly while keeping the painting from warping. Only if the wet painting’s surface can tollerate being placed face down (minimal impasto, no lifting paint, not sticky, and you are willing to risk this on your own), I would recommend the following. Remove any debris from the surface. Prepare an absorbant surface (blotter, unprinted newsprint, etc.), place a piece of non-woven, breathable, plastic barrier layer (Hollytex, thin Pellon, Remay, etc.) on the paper. Finally, place a sheet of glassine down. Place the painting face down on the prepared surface. More absorbant material on the reverse, and finally, a board of some type. Weight the whole package down – stacks of books are good. Periodically change the absorbant material on the reverse until the painting is dry.

If you find that the glassine has stuck to the surface of the painting leave it in place. Do not try to pull it off. The glassine should be removed by a conservator, although there is no pressing rush to have it removed immediately.

When dry, you can reattach it to the support. If there is glue residue on the reverse of the painting and the floating frame, see if you can figue out which orientation they were originally glued. This way the bumps on the painting will match the depressions on the frame and you will have a closer glue join. If the floating frame can be attache with the painting face down as it was dried, just apply a very think layer of PVA to the original glue line on the frame and reverse of the painting with a brush, place the frame in position and weight the frame. Also, place some weight on the center of the painting to keep it from bowing.

If the floating frame projects above the surface of the painting you will have to work with the painting face up. Find some blocks the same thickness of the frame elements on the reverse. Place the frame face up and distribute the blocks to support the painting. Apply the PVA to the inner edge of the frame and reverse of the painting as above, place the painting into the frame. Place a fresh sheet of glassine on the surface followed by the breathable plastic material on top of the glassine, and add padding as necessary. place weight along the edges and make sure that the weight is not bowing the panel. If it is, readjust the blocks on the reverse to prevent the warping.

We think that covers everything. Please remember that these are just suggestions. Not having examined the painting we can’t assure you that this is the best course of action. There is inherent risk any time a painting’s surface is put in contact with anything, so please be aware that should you follow the advice given above, you are doing so at your own risk.