Why does antique mirror glass develop dark spots?

The dark spots, known as foxing, occur when moisture and air seep behind the glass over decades and react with the silvering or mercury backing. This chemical breakdown creates the mottled patterns and clouding that collectors prize for their atmospheric and authentic appearance.

How do I hang a heavy overmantel mirror?

Heavy overmantel mirrors require secure fixing directly into wall studs or masonry using appropriate brackets suited to the weight of the timber and glass. Professional installation is recommended due to the substantial combined weight of the wood, gesso, and thick antique glass plate.

Are foxed glass mirrors still useful for reflection?

While the foxing creates dimming and distortion, they function adequately for general room reflection while serving primarily as decorative wall art. The aged plate softens the reflected light, casting a warm and ambient glow across a room rather than a crisp image.

How do I clean an antique mirror safely?

Clean the glass gently using a soft, dry microfibre cloth to remove dust without disturbing the delicate surface of the plate. Avoid liquid glass cleaners and harsh chemicals, as moisture can seep behind the frame and accelerate further deterioration of the foxing.