Purchasing an art nouveau desk requires all the usual criteria for purchasing a large piece of furniture, plus those for buying an antique. Unless you are purchasing for resale, you will want to buy a piece that fits your decor in size, style, and functionality. Since it is an antique, you should also pay close attention to quality, noting damage, repairs, and overall condition.
Before you begin shopping for an art nouveau desk, you need to do some research. The more you understand about the time period and characteristics of art nouveau furniture, the better chance you have of avoiding fakes or reproductions. For instance, art nouveau was a movement, starting sometime in the 1880s and lasting until World War I and included art, furniture, architecture and other media. Some of its characteristics are long lines, like vines, flowers, or flowing hair. It also included exotic details and influences from other countries.
Determine the size and color of the desk you need for your space. Measure the space where you intend to locate the desk for height, width, and length. Make sure that you leave enough room for a chair and comfortable maneuverability of drawers and doors. This will be the maximum size of the desk.
The color should coordinate with the other decor in the room. You don't have to choose the exact same wood grain or stain color, but keep it in the same family, unless you want the desk to serve as an accent piece. If this is the case, it should be boldly different so that the decor choice is obviously intentional.
Since even the latest art nouveau pieces are several decades old, they will probably show some wear. Often, you can spot a fake when a retailer assures you that the piece is authentic but the condition is too good to be true and the price is far too low. Of course, if you believe that a piece may be real, but you are unsure, you can call an antiques appraiser for a professional opinion before you buy. Only do this if you believe it is worth the extra money as an appraiser will charge a fee.
When you look at an art nouveau desk, inspect it carefully for damage and signs that it has been repaired. Often the hardware, like knobs and hinges, may not all match or may look significantly newer than the rest of the piece. Look carefully at all the wood, and note any areas that are a different color or that have a different wood grain. These are probably areas which were damaged and repaired. Check the inside of cabinets and drawers. If they are lined with cedar or oak, it's a good sign of high quality craftsmanship.
The condition plays a major role in the overall value of a piece. You should not pay top price for an art nouveau piece unless the condition is immaculate. Even if you are purchasing a piece with no intention of reselling, try not to pay more than a reasonable price. Someday you may decide to resell or your heirs may decide not to keep the desk. It may be tough to resell an art nouveau desk knowing that you paid much more than it is worth.