Authentication Guide

How to Spot an Original: The Collector’s Guide to Authenticating Porcelain Signs

The “Golden Age” of advertising (1920s–1950s) produced signs that were meant to last a century. Today, modern “fantasy” signs and reproductions flood the market. Use this guide to separate the investment-grade originals from the modern fakes.


1. The “Shelve” Test (The Tactile Edge)

Authentic porcelain signs are created using a layering process. Each color is a separate layer of glass frit fired at over $1400^\circ F$.

  • The Test: Run your finger across the transition between two colors (e.g., a white letter on a blue background).
  • The Result: On an original, you should feel a distinct “shelf” or “lip”—a slight rise where one color sits on top of the other. Modern fakes are often flat, digital prints or thin enamel that lacks this physical depth.

2. Inspecting the Backside

The back of a sign tells a deeper story than the front.

  • The “Orange Peel” Effect: Most vintage signs have a “stippled” or “orange peel” texture on the back, often in a dark cobalt blue or black. This was a protective base coat.
  • Natural Patina: Look for “rust creep.” On an original, rust starts at the edges or mounting holes and works its way under the porcelain. If the rust looks like it was “painted on” or is uniform across the whole sign, be suspicious.

3. Grommets and Mounting Holes

How the sign was intended to be hung is a major clue.

  • Originals: Usually feature heavy brass, lead, or copper grommets. These were designed to protect the porcelain from the pressure of a screw.
  • Reproductions: Often have simple drilled holes with no grommets, or shiny, modern steel grommets that haven’t oxidized.
  • Wear Patterns: Look for “keyholing”—slight elongation of the hole caused by years of the sign swinging in the wind.

4. Manufacturer Marks & Dating

Most major porcelain companies signed their work. Look for small text at the very bottom edge:

  • Common Makers: Ingram-Richardson (Ing-Rich), Veribrite Signs, Texlite, or P&M.
  • Dated Codes: Many signs from the 1930s–50s are dated (e.g., “3-46” for March 1946). If a sign claims to be from the 1920s but uses a font or logo that wasn’t designed until the 1960s, it’s a “fantasy” piece.

5. The “Smell” & “Reflection” Tests

  • The Reflection: Hold the sign at an angle to a light source. Original porcelain has a “liquid” or “glassy” reflection. Modern fakes often have a “plastic” or “dull” sheen.
  • The Smell: It sounds strange, but old signs don’t smell. If you get a whiff of fresh paint or chemicals, the sign has likely been “touched up” or was manufactured recently.

Expert Note: If the price seems too good to be true, it probably is. Rare $30″$, double-sided signs from the 1940s rarely sell for “thrift store” prices.