Conservation Framing 2018-03-14T22:07:30+00:00

Conservation Framing

When well chosen and considered, the picture frame can afford a high degree of protection to an artwork, in addition to enhancing its appearance. The smallest details can have a significant impact on the painting’s preservation, both in the short and especially, in the long term. All too often I observe damage which has resulted from unsuitable or inadequate framing materials and methods.


Many works which arrive in my studio are held in their frames with nails bent down over the back edges of the stretcher or driven through its back edges. Nails may shift, leaving the painting loose in the frame, and the frame and/or stretcher may be damaged. When the nails or other fasteners have been countersunk, they can be very difficult to extract, jeopardizing the stretcher and painting.

Offset clips used to secure paintings in frames are screwed into the back of the frame (NOT into the back of the painting). When the painting is flush with the back of the frame, straight mending plates or turnbuttons, such as those seen at right, are utilized.

A much superior method is to secure the painting in the frame with the use of zinc-plated or brass offset clips, which are simply screwed into the back of the picture frame, and held snug over the back of the painting. Offsets come in standard depths or may be shaped to accommodate the work. The depth required varies depending on the degree to which the painting projects from the back of the frame.  Ideally, the frame is at least deep enough to cover the sides of the painting. On the front, it should project above the surface of the painting to maximize the frame’s protective function.

A Good Fit

The painting must not be forced into the frame opening; a small gap should be provided around all sides of the work to allow for movement of the stretcher (or other support). If the gap is considerable, as is often the case with older frames, it should be filled with a good quality foam strip* to provide a secure but cushioned fit. Finally, it is important to ensure that the frame rebate/rabbet edge in contact with the front edges of the painting is smooth and ideally, cushioned with acrylic felt, velvet or archivally safe cushioning foam* to prevent abrasion.  Mechanical damage, once begun, may spread beyond the rebate area of the painting, as shown in the portrait below.

*the foam type, as with any material in contact with an artwork, is important – consult a conservator.

The results of poor storage are evident here, as are paint losses and abrasions along the front edges caused by direct, damaging contact with the frame rebate.

Hang Tight!

Wood strength may diminish over time and its hardness and density is variable, so it is a good idea to periodically check the hanging hardware in the back of your picture to ensure it is secure.  Hanging hardware should always be inserted in the frame, not in the back of the painting. Of course the frame joins must be secure or the frame could fall apart; any weak component may put the painting at risk.

RECOMMENDED. Various styles of bar (left) and strap or “D-ring” hangers (right) are safe when selected for the weight and size of picture and fastened in sound wood with screws of adequate size and length.

NOT RECOMMENDED. Screw eyes are apt to bend (the screw eye at left was removed from an old frame), break, or pull out of the wood. The small brass screw eye at right was removed from a four foot square painting!

Protective Glazing

Works of art on paper should always be framed with protective glazing (glass or acrylic e.g. “Plexiglas”), which must be held off the surface of the artwork. Typically this is accomplished with a mat board “window,” which also has an aesthetic function. Many people are surprised to learn that even oil paintings benefit from protective glazing and furthermore, there is an historical precedent for doing so. Again, the glazing must be held off the surface of the painting, either in a frame channel or with the use of a suitable spacer or inner frame component.

The decision of whether or not to protect the surface of a painting with glazing and the choice of glazing type depends on personal preference, the size of artwork, ability of the frame to accept glazing, display location, and likelihood of travel.  A painting in a public/high traffic location where accidental or intentional damage is likely would be one obvious candidate.  Works which have extra vulnerability  (e.g. textured paint surface, history of flaking and instability) will certainly benefit from protective glazing, which also helps buffer works from rapid environmental changes.

Acrylic paint is inherently softer and more easily damaged than oil paint, and may also be more difficult to clean, so the use of protective glazing is an excellent preventive measure.  Similarly, highly textured paint surfaces regardless of medium type, readily accumulate dirt on projecting “impasto,” so cleaning them is more difficult, time-consuming, and costly.  When a painting cannot or should not be varnished, glazing offers not only equal, but in many ways superior protection and best of all, can be easily removed without any risk of adverse effect on the artwork.

Photo courtesy of Tru-Vue Inc. Both products shown offer UV-blocking but Museum glass has an anti-reflective coating.

High quality conservation glazing (manufactured to block much of the damaging ultraviolet radiation which enters your home through ordinary window glass) is now readily available and more affordable than when first introduced. If glare is a concern, good quality conservation glass is available with reflection control or an anti-reflective coating. While anti-reflective coatings add to the cost, they offer good value for their superior optical qualities.

Original Frames

Sometimes artists will have designed and/or made their own picture frames, and this may a documented practice, or even indicated directly on the frame. Knowledge of an artist’s techniques and preferences may also include their framing preferences as documented by a curator, conservator or other professional. Under these circumstances, it is essential to retain the original picture frame as an integral component of the artist’s vision.

When an historic work is received with a historic picture frame, it is usually possible for me to ascertain whether or not it is original to the painting (even though the frame may be older). In general, I encourage my clients to retain the original framing. If the frame requires treatment, I can provide a separate assessment and cost estimate for its repair. If the frame is of inferior quality, irrecoverably poor condition, the client objects to the frame, or does not wish to have the frame treated, we can choose a new moulding.  I carry a select line of frames, many with relatively deep rebates that paintings on canvas require. If a replacement frame is chosen, I may still advise the client to label and retain the original frame.

This portrait of Dorothy Swan by James McIntosh Patrick is shown before treatment in an original frame which had been overpainted dark grey.

This portrait of Dorothy Swan by James McIntosh Patrick is shown before treatment in an original frame which had been overpainted dark grey.

Portrait of Dorothy Swan after treatment. The client opted for a custom reproduction frame while retaining the original frame in storage. The new frame was painted the original green colour as revealed in loss areas on the original.

Portrait of Dorothy Swan after treatment. The client opted for a custom reproduction frame while retaining the original frame in storage. The new frame was painted the original green colour as revealed in loss areas on the original.

The before treatment photo of the above portrait shows the original frame overpainted dark grey. The frame’s condition at the time of overpainting was unknown, lending uncertainty to the success of possible frame restoration; labour-intensive removal of the overpaint might have revealed a heavily damaged surface and a disappointing result for the client.  The frame moulding was fairly simple and could be reproduced without much difficulty.   After a carpenter reproduced the frame, I painted it to match the original muted green colour, as shown directly above. The depth of the reproduction frame was also increased to afford better protection to the painting.

Protective Backings

Rigid backing boards are an essential protective component of the framing assembly.  Backing boards:

  • protect the back of the work from mechanical damage
  • prevent soiling of the (usually) uncoated back surface of a painting
  • buffer the painting from changes in relative humidity (RH)
  • serve as an acid-free surface on which to attach encapsulated inscriptions, labels, etc.

I usually use a chemically inert, corrugated plastic board known as Coroplast, which is available in a variety of thicknesses, 4 mm being the most common. The backing board may be combined with a foam tape seal around the outer edges to enhance the environmental buffering and soiling prevention. The inclusion of a moisture-absorbing material such as mat board inside the final backing further enhances RH buffering.

Depending on the painting type and framing configuration, the backing may be attached directly to the back of painting, held in place over the back of the painting, or secured to the back of the frame. I utilize protective backings as a standard part of the treatment procedure, and will determine the best combination of features for your work.