Who made your window? Reading a Tiffany signature

The question we are asked most often is whether a window is "a real Tiffany." The honest answer is that it depends on what you mean, and the window itself usually tells you.

**One studio, several names.** Louis Comfort Tiffany's glass business operated under different names as it grew: Louis C. Tiffany and Company, the Tiffany Glass Company, the Tiffany Glass and Decorating Company, and finally Tiffany Studios. The name on the window dates it. A panel signed "Tiffany Glass and Decorating Company" with a copyright of 1898 is earlier than one signed "Tiffany Studios New York 1917," and both are genuine. We have handled windows carrying each of these marks, and the difference matters to buyers.

**Where to look.** The signature is usually painted or etched on a small panel of glass in the lower right corner, often in a border or in the inscription band beneath the picture. It can be tiny. On one window we handled, the words "Tiffany Studios New York" sit in a strip of green glass no wider than a finger. On another, the signature reads "Louis C. Tiffany N.Y." in script, which points to an earlier period and sometimes to the founder's personal involvement in the design. Bring a torch and look from inside with daylight behind the glass.

**The glass says as much as the signature.** Tiffany's studio made its own opalescent glass, in which the colour is in the glass itself rather than painted on. Drapery glass, folded while molten so a robe has real ridges you can feel, is a Tiffany hallmark. So is the layering of two or three sheets to build a sunset or the depth of a landscape. Faces and hands are painted, everything else is glass doing the work. A window that relies on painted detail everywhere is probably from another studio, however fine.

**Who actually made it.** Tiffany was president and art director, but the windows came from a studio of designers and craftspeople: Frederick Wilson for the great figure windows, Agnes Northrop for the landscapes, Clara Driscoll and her department for much else. Letters from Driscoll discovered in recent decades have changed how the studio's work is understood. A window can be "a Tiffany" and also the work of a named designer, and knowing which one is part of the provenance we record for every piece we sell.

If you think you have a Tiffany window, photograph the lower corners and any inscription and send them to us. We can usually tell you the studio period from the mark, and we will say so plainly if it is not what you hoped.