About
Mounting Large-Format Contemporary Photographs
A tintype is a monochrome direct positive on metal plate support. Like the ambrotype created on glass plate, it is a negative image that is seen as a positive, due to the dark support, the silver grains composing the light parts of the image. The resulting pictures are usually small formats, the most common being the "visiting card" (sixth or ninth plate), the "jewel - portrait" (2.5 × 3 × 3 cm) or the "postage stamp" (1.2 × 2.5 cm) formats. Full plate tintypes (16.2 × 21.6 cm) and landscapes views are the rarest.
Historical period of production and use
One of the characteristics of contemporary photography is the frequent use of large formats. The exhibition, and necessary mounting, of these large photographs raises technical issues related to ensuring that the image remains flat, isn’t too heavy to handle and doesn’t get damaged easily.
Matting—the traditional way of presenting photographs—isn’t viable for formats over 80 x 120 cm, either from a practical or an aesthetic standpoint. One good solution is to dry mount the image on a flat, light, rigid surface. The most common choices are aluminum; polymethyl methacrylate, or PMMA (Plexiglas®, for example); expanded polyvinyl chloride, or PVC (like Forex®); a composite panel made of aluminum and polyethylene (like Dibond®) or a composite panel of aluminum and polyurethane (like Kapafix®). The image is professionally laminated using a double-sided acrylic adhesive. A drawback of this type of presentation is that it is not reversible. Different hanging systems can be used. The image can be framed (under glass or not, in a floater frame , etc.) or a frame-like structure can be mounted on the back of the panel. The latter option is often preferred because it makes the mounting system almost invisible.
© Stéphane Couturier (né en 1957), « Jardin des Tuileries - Paris 1 – 1998 » 1998, 1/5, Epreuve couleur à destruction de colorants (Cibachrome/Ilfochrome) sous Diasec contrecollé sur aluminium, 160 x 125 cm, Fonds municipal d’art contemporain de la Ville de Paris (FAC). © Stéphane Couturier / FAC / Roger-Viollet
Schéma Diasec © ARCP / Mairie de Paris, 2017
Diasec® mounting
Diasec® is a commercial mounting process with a characteristic appearance. It was patented in 1972, and ever since its use has required a license agreement. It involves bonding the image side of a photograph to a translucent surface. In addition, the back of the image can be protected by dry mounting it on another surface, as described above.The Diasec® patent covers the bonding process, which uses a silicone-based primer. The translucent panel usually employed is PMMA, which is inexpensive and easy to handle, has excellent optical characteristics and can incorporate a UV inhibitor and anti-reflective treatment. It is also relatively light and very impact resistant.
The PMMA becomes the surface of the artwork because the bonding process is irreversible. Except for rare adhesion problems (localized detachment) conservation issues are usually mechanical, especially due to the fact that PMMA is not very scratch resistant.
Bonding the image side of the photograph has an aesthetic impact on the work, increasing its contrast and its color saturation like a varnish would. The effect is emphasized by the shine of the surface of the PMMA (although a matt material can also be used).
Photographs mounted with this process are common in collections of contemporary photography.
1. A traditional frame is made from molding that is recessed on the back and covers the edge of the work. It includes a sheet of protective glass. A floater frame (or “caisse américaine” in French) uses molding that isn’t recessed and there is no overlap with the artwork. A space a few millimeters wide separates the frame and the edge of the work, which is mounted on a flat, rigid support underneath.
2. The term “face-mounting” is used to describe photographs mounted using the proprietary Diasec® process as well as others using a similar unlicensed technique.
3. The primer is an adhesive preparation applied between the photograph and the PMMA. It is perfectly transparent.
Cross-section of a photograph mounted using the Diasec® process
Credits
Visual Glossary of Photographic Processes © ARCP / Mairie de Paris, 2023
Glossary
Albumen Print
Aristotype
Autochrome
Carbon Print
Chromogenic Prints
Collodion Glass Plate Negative
Portrait Crayon
Cyanotype