Originally used to advertise everything from soda to gasoline, vintage porcelain sign are prized by collectors for their vibrant artistry and as a link to a simpler time. These signs, once common, are now rare artifacts that recall a bygone era when gas cost a nickel and squads of uniformed attendants stood ready to pump your car. Porcelain enamel signs are so durable they often survive from the 1920s to the present day in their original condition. However, with their popularity has come a rise in reproductions and fakes. Authenticating an antique porcelain sign is a meticulous process that requires historical knowledge, material analysis and expert scrutiny.

The most valuable porcelain enamel signs are those with provenance, a documented history of where the sign came from and when. These are considered museum quality and can command a price tag of thousands of dollars. Many buyers treat their collection of these rare signs as an investment, acquiring them for the long-term.

Many porcelain sign reproductions are made by machines that are not as precise as the old processes of applying colored powdered glass onto a canvas that was then kiln-fired to create the thick enamel coating. The resulting product is not as smooth and the color can be spotty. Authentic porcelain is made by hand, which means the color can be applied in layers and then kiln-fired again to achieve a smooth enamel surface. If you rub your finger over the surface of a real porcelain sign, you can feel those layers. A fake or reproduction will have a much smoother surface.

While most collectors are willing to pay top dollar for an authentic porcelain sign, not everyone can afford the cost. Some collectors prefer to collect smaller porcelain signs that are less expensive. For example, door pushes, which retailers attached to the part of their front doors that customers pushed to enter, are a popular small form that can be easily handled by collectors. Another coveted small porcelain sign is the pump plate, which appeared on early gasoline pumps and identified the company brand name and octane rating.

When buying a porcelain sign, it is important to select the seller carefully. The most legitimate sellers will not only sell the sign, but also stay connected with their collectors. They will offer to buy the sign back from you at a later date and resell it to someone else, which is beneficial to both of you. In addition, the legitimate seller will want to keep a relationship with their collectors because the value of their items increases over time.

Another identifying factor of an authentic porcelain sign is the alignment and spacing of the mounting holes. While it is difficult to determine this from photographs, a little research or an expert can help you decipher if the hole alignment is correct. Reproductions can be made with the same mounting holes, so this is a good way to differentiate them from real ones.