Mounting Large-Format Photographs: A Temporary and Reversible Alternative to Dry Mounting

On top of the usual considerations for lighting controls and protecting the artwork from physical damage, displaying a large-format photograph necessitates a mounting method that will ensure the object remains physically stable and won’t sag under its own weight. Over time, a large-format photograph that’s only mounted from the top edge or from the corners will sag, creating increasingly visible cowl-shaped undulations in the center of the object. We want to avoid this as much as possible for two main reasons: a) it is distracting to the viewer, and b) this type of damage is almost always irreversible.

The rate of this type of damage varies, depending on a number of factors, including: the ambient temperature and relative humidity of the exhibition space, the thickness, type, and quality of the photo paper, and the size of the artwork itself. But in any case, sooner or later, the photograph will begin to show signs of planar distortion, and at that point it’s usually too late to do anything about it.

There are different methods that can mitigate and event prevent sagging. A popular technique is dry mounting, whereby an image or photograph printed onto a thinner primary support (i.e. photo paper) is fully adhered to a thicker, sturdier secondary support (i.e. cardstock or mat board) using an adhesive interleaving. With a few exceptions, dry mounting is fairly safe for most types of printed media, and thanks to advancements in the quality and reliability of the materials used, museums and galleries can opt to dry mount large-format photographs and still expect the finished product to age relatively well. Dry mounting also prevents the dreaded c-shaped handling dents that are a far-too-often occurring form of physical damage due to improper or over-handling.

But dry mounting also has some drawbacks. A perfect finished product isn’t a guarantee; an errant hair, adhesive residue, or some other form of impurity – which under normal circumstances are far from any real cause for concern – will invariably escalate the harm they can cause during the heat and pressure stage of dry mounting, which will unfortunately lead to permanent and visible damage to an artwork. Also, by its very nature, dry mounting is permanent, which means that any accidents that happen during the dry mounting process are irreversible.

The method we used to mount a series of 4 large-format photographs for the upcoming Biennial achieves a similar desired result as dry mounting, whereby the photographs are supported against a thick, sturdy secondary support, evenly distributing the mechanical stress of being upright for an extended period. We also made our own hinges using materials that are chemically inert and 100% reversible. Essentially, this allowed us to make a non-permanent mount for the photograph that would be strong enough to prevent sagging, and wouldn’t interfere at all with the aesthetic of the photograph.

We used a stable and reversible adhesive called Lascaux. Like similar acrylic glues, Lascaux is easy to work with when wet, and stays flexible and slightly tacky when dry. Once fully dry, the glue is able to be reactivated with either heat, or alcohol solvents. By mixing two different viscosities with some distilled water, we created a glue that was exactly what we needed: it would be liquid enough to slightly permeate the hinging material (i.e. non-woven polyester) while wet, and not so tacky after it dries that it is too difficult to work with.

If you’re curious, here’s the recipe:
- 2 parts Lascaux 498 (thicker)
- 1 part Lascaux 360 (thinner)
- 1 part distilled water

Image 1: Prepared hinges (measuring about 2 x 4 inches), the glue is only applied to about half the width of the strip

 

We created our own hinges by applying 3 coats of our glue mixture to a large sheet of non-woven polyester, and cutting them into usable strips. After cleaning the verso of the artwork with a soft brush, we were ready to start applying our hinges.

Image 2: The photograph has been placed face-down on a clean working surface, brushed clean with a soft brush, and weights are set down to ensure the artwork remains flat and immobile

 

During the application process, it’s important to keep the artwork under evenly-distributed weights. This ensures that the artwork remains as flat as possible. The verso of the photo paper of these particular photographs have a slightly fibrous texture, which means that the glue has a great surface to adhere to.

Image 3: The hinges are miter-cut in the corners, and pressed into place

 

Image 4: The hinge is set to the artwork using a heat spatula set to 85 degrees Celsius

 

We never apply the spatula directly onto the hinge, as the glue can leech through and stick to the spatula. To avoid this, we use a clean piece of release material (made of the same non-woven polyester material used to make the hinges) to act as an interface that will allow the heat to pass through it, but won’t stick to the hinge.

Image 5: Hinges are placed at equal intervals around all four edges of the artwork

 

Image 6: Once the hinges are all placed, the photograph is ready to be secured to the secondary support

 

Image 7: A sheet of 16-ply acid-free mat board (cut to 2 millimetres larger than the artwork on all sides) is set down over the artwork, and the hinges are ready to be secured

 

We’re very choosy when it comes to the materials that we use in proximity to – or in this case, in direct contact with – the artwork. This is done in an effort to minimize as much as possible the deterioration of the photographs due to pollutants introduced from other materials.

Image 8: A length of archival pressure-sensitive tape secures the hinge around to the back of the secondary support

 

Image 9: The hinges are secured in a deliberately random pattern to avoid a lop-sided distribution of the overall tension, and the corners are mitered

 

The final product provides an even weight and tension distribution for the artwork in a way that is safe, aesthetically appropriate, and 100% reversible.

 

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Supported by

Scotiabank Photography Program

 

Soutenu par

Programme de photographie Banque Scotia