Through a glass darkly
You move to a bigger house and, all of a sudden, those small pictures that were perfect in your old place look like postage stamps on acres of blank wall. Large pictures can be so expensive, so what's the alternative?

It can all be done with mirrors. If you compare the price of a good mirror with a decent picture, you find that the mirror is much cheaper per square inch. Never mind the quality, feel the width, as they say - but with mirrors you can have quality and width.

An elegant 19th century overmantel mirror

Mirrors have always provided the focus of well-furnished rooms, and their frames are often very beautiful. In the 18th century, architectural Palladian frames were superseded by flamboyant Rococo versions. These were followed by the elegant neo-classical designs of the 1770s, then by the more flamboyant Regency designs, typically with convex mirror plates - a new invention at the time.

Two of the most important factors to consider when buying an 18th- or 19th-century giltwood mirror are the age of the mirror plate itself and the condition of the gilding. An original mirror plate will add a great deal of value. Mirror plates from the 18th and early 19th centuries are generally not as thick as later plates. A quick way of checking the thickness is to take a biro or pencil, place the point on the plate and look at the distance between the tip on the plate, and the tip reflected. Earlier plates often look cloudy and speckled. This is where the reflective mercury silvering has degraded. Many collectors prefer a mirror plate that you can barely see your reflection in.

A carved frame that retains its original gilding will add value too. As the original layer of gilding began to lose its bright sparkle, it would be re-gilded - rather like another lick of paint - and so some 18th-century mirror frames can have four or five layers of gilding. If you're lucky, you might come across a mirror that has been re-gilded but retains much of its original first layer of gilding below. By dry-stripping the later layers, you can reveal the wonderfully preserved original layer. It's a painstakingly slow and expensive process, but the rewards more than make up for it.