resilvering

Resilvering is the process of renewing the reflective silver backing on the rear surface of a glass mirror. It is used when the original reflective layer has deteriorated, tarnished, or become damaged, reducing image brightness. In antique practice, mirrors were backed with silver or an amalgam, and resilvering may also involve removing an old backing and replacing it with a new silver coating, sometimes after addressing hazardous remnants from earlier methods.

The restoration is typically performed by professionals and involves cleaning the glass, removing the old backing if necessary, and applying a silvering solution. A common approach uses a silver nitrate-based bath to deposit metallic silver onto the back of the glass, often with a thin copper strike for adhesion, followed by sealing with a protective lacquer or additional backing layers. Modern variants may employ electrochemical or vacuum-deposition techniques, though chemical silvering remains common for repairs of historical mirrors.

Key considerations include the condition of the glass substrate, the integrity of edges, and the presence of any existing damage or delamination. Not all mirrors are suitable for resilvering; severe structural flaws or degraded backing materials may require replacement of the entire mirror. The procedure can be hazardous due to chemicals and glass handling, and is typically done by specialized restoration services. Aftercare involves protecting the surface from humidity and cleaning with non-abrasive methods to preserve the new reflective coating.

Alternatives include replacing the mirror with a modern sheet or choosing to frame or display the item without restoration, depending on value and condition.