A mounting press is a specialist piece of equipment used in photographic print finishing and presentation, designed to apply a combination of controlled heat and firm, even pressure to bond a photographic print securely to a mounting board or other support material using a heat activated dry mounting tissue. The simultaneous application of heat and pressure softens the thermoplastic adhesive coating of the mounting tissue, causing it to flow and bond uniformly across the full surface area of the print and mount board, creating a smooth, flat, and permanently adhered result free from bubbles, wrinkles, or areas of poor adhesion that can compromise the appearance and durability of the mounted print.
The mounting press consists of a flat, rigid heated platen - typically surfaced with a smooth, non-stick material - that closes down onto a correspondingly flat lower bed with sufficient pressure to ensure intimate contact between all layers of the mounting sandwich throughout the bonding process. The temperature of the heated platen is thermostatically controlled and adjustable, allowing the press to be set to the correct activation temperature for the specific dry mounting tissue being used, as different tissue formulations require different temperatures to soften and bond effectively. Most mounting presses also allow adjustment of the closing pressure to suit different combinations of print, tissue, and mount board thickness.
The dry mounting process carried out in a mounting press typically follows a carefully sequenced procedure to achieve the best results. The mounting tissue is first tacked lightly to the back of the print using the tip of a tacking iron - a small handheld heated tool - to temporarily bond the tissue in position without committing to the final placement. The print and tissue are then trimmed together to the desired size, positioned on the mount board, and the assembly is placed between protective release paper sheets before being inserted into the preheated press. After the appropriate dwell time at the correct temperature, the press is opened and the mounted print is immediately transferred to a flat surface under a weight or cool press to set flat as it cools.
Mounting presses are available in a range of sizes from small desktop models suited to prints up to approximately A3 or tabloid size, through to large floor standing professional models capable of accommodating very large exhibition prints and display graphics. While dry mounting with a mounting press produces an extremely secure and visually clean result, it is an irreversible process that permanently bonds the print to its support and is therefore not considered appropriate for archival or conservation mounting of valuable or irreplaceable prints, for which reversible conservation mounting techniques are preferred.