Definition: A substance that bonds two materials together.
Adhesives are bonding agents used in picture framing, art conservation, and general construction to hold materials in place. They can be natural or synthetic and are selected based on their bonding strength, flexibility, reversibility, and long-term stability. In framing, adhesives are often chosen with special consideration for archival safety and their impact on artwork over time.
Not all adhesives are suitable for archival framing. Some may yellow, become brittle, or release harmful chemicals (off-gassing) as they age. Conservators often prefer reversible adhesives that can be safely removed without damaging the artwork.