Volume 5, Number 1, March 1983, pp.3-4

A New Mounting System

(cross section of mounting system)

Paintings conservators often confront the question of how to deal with fabric supports which are composed of multiple pieces of fabric. The effect of the seams on the paint films from treatment requires special attention.

Such was the problem presented by several large paintings from the Panorama Series painted by C.C.A. Christensen circa 1875. The twenty-two paintings composing the series were originally sewn together and passed along a roller in filmstrip fashion for all who would pay to see them as the artist and his family passed from town to town in their covered wagon. It is believed that most of the proceeds were donated to furthering a missionary cause. The paintings began with the First Vision of Joseph Smith, president and prophet of the Church of Jesus Christ of Latter-day Saints, which marked the beginning of Mormon history in the "latter-days." The twenty-one paintings which followed vividly and candidly portray and interpret the expansion of the West into Nauvoo, Illinois and then over the plains to the Rocky Mountains as experienced by the Mormon pioneers. Painted in thick tempera on a light canvas, each painting measuring 6'6" x 9'6", the roll of paintings has seen quite a variety of storage conditions, ranging from being rolled and unrolled to being stored in a warehouse that burned down. They are, generally speaking, stained, cracked, abraded, and very unstable. In 1970 a paste lining was applied prior to a national tour which ended in 1978 when I was sent to San Jose to pick them up after a fork lift had gone through the shipping crate. Plans were still in the works, however, to use these paintings for traveling exhibitions, and in 1982 funding was obtained for their conservation prior to a heavy exhibition schedule. Upon considering future use and the very delicate and unstable nature of the works themselves, it was decided that solid honeycomb panels would be a positive step toward their long term preservation and protection.

However, several painting supports are composed of multiple pieces, and therefore the need to isolate the seams from the panel and eliminate the potential for distortion which would result with conventional mounting and lining techniques was studied. Removal of these seams was undesirable for several reasons; loss of strength in the support as a whole, but particularly at the seams would require a greater amount of direct intervention. Removal of the seams and the subsequent weakening of the support structure would also limit the options for such treatments as flattening or stretching.

Spacing the seams away from the backing surface and isolating them from pressure appeared to be the best way of avoiding deformation. This procedure would preserve the strength and create a barrier between the original painting and the panel making this intervention more reversible. The spacing boards (and other layers) are custom made to fit the specific needs of each painting. This project required the space of two four-ply acid free rag boards to raise the seams high enough. These were cut to follow very closely the unevenness in the seams. The two mounting boards were coated on their common sides with Rhoplex 234 and when dry were coated with a layer of PVA heat seal adhesive or Beva. After drying for twenty-four hours the boards were adhered to each other on the hot table at 160°. F at full pressure. Excellent results were also obtained with a hand iron and a brayer.

In the case of larger paintings, a continuous layer of acid free stock is not possible, and several pieces may need to be used. The unevenness of the joins will transfer to the original and therefore must be covered to form a continuous layer. With the same adhesive system used for attaching the spacing boards to each other a layer of fabric is applied to the spacing boards on the side which will be against the original work of art. This layer spans the cracks and homogenizes the surface.

The spacing boards, now composed of two four-ply boards, and a layer of fabric, were prepared for mounting with a coat of Rhoplex 234 which serves to keep the fabric from absorbing the adhesive layer. (Consistency depends on absorbency of fabric). After drying, a very even layer of heat seal adhesive was applied and let dry for twenty-four hours. This sandwich construction was inspected before mounting for bubbles and voids. The original fabric will have already undergone cleaning and must also be flat and free from dust and particles.

The process of mounting of the spacers to the original is best done under observation with the painting face up. This requires tacking the spacers to the reverse with a hand iron before turning the whole over. The adhesion in this case took place at 110°. F at five lbs. pressure. Again, excellent results may also be obtained with a hand iron and brayer. Mounting has also been done face down with no complications, but non-visible complications could be disastrous and time consuming.

An additional layer of fabric was applied to the back of the spacing board (heat seal adhesive) after the original painting was mounting to the front to seal off the cracks around the seams and to isolate original fabric from possible adhesive contamination. With this layer of fabric isolating the original painting and backing boards the choice of an adhesive to mount the whole to the panel is less restricted. While heat seal adhesives are still a choice, other cold setting, non-reversible adhesives are also an option, and especially attractive if the non-heat-conducting low cost Kraft honeycomb panels are used.

The goal of such a spacing system as described above is to provide a mounting procedure which allows for the preservation of seams yet aids in avoiding distortion in the original, a result of conventional mountings to solid surfaces. An added bonus, is the isolation of the original from the panel aiding in reversibility. Theoretically, this concept should also be applicable using other adhesive systems such as hot melt or cold settings techniques for mounting the original painting on fabric to the auxiliary supports.

Specific considerations were made as to weight of fabrics, number of layers of rag board, and adhesive systems in relationship to this specific project's needs. There are foreseeable variables in this technique as predetermined by the projects themselves. Although it may not be a cure for all paintings with seams, nor will it cure the common cold, it was a very good, safe option for a specific need. I will undoubtedly continue to review this type of an option critically and will appreciate hearing pros and cons as you test the limitations of such an intervention.