Things You'll Need
Instructions
Research the player to determine the approximate age of the baseball. For example, if you have a baseball signed by Thurman Munson, it's important to know that he died in 1979. Any authentic signature from Munson is more than 30 years old.
Examine the baseball and the signature for signs of wear. Older signatures will fade over time and authentic older baseballs are almost always discolored from age.
Rub your finger carefully over the signature. Feel for grooves caused by pen pressure. Stamped signatures are flat and smooth.
Hold the baseball under a lamp and tilt it. Watch how the light reflects off the signature. Real ink signatures reflect light inconsistently and in different colors, whereas pre-printed signatures will appear glossy and uniform.
Use a magnifying glass to study the signature. Real ink has rough edges and trails off at the end of a stroke. By comparison, stamped signatures have consistent, sharp edges.
Compare the signature with other authentic signatures from that player. Pay attention to characters and pen strokes that are the same in different samples and verify that your autographed baseball has these characteristics.
Submit your baseball to a professional authentication service like PSA/DNA or JSA. For a fee, these companies will determine if the signature is a real autograph and whether it is authentic. If your autographed baseball is certified authentic, this will raise its value.
Research the item to see if there are others similar to yours. For example, you may find that a certain baseball is, in fact, a mass-produced stadium giveaway item.