For a true collector and fan, or a re-seller, authenticating autographs is the most important step to take, before you purchase an autographed item, unless you are witnessing the athlete sign it yourself.
Experts and reputable sellers have many means at their disposal to check on an item’s authenticity, from simple comparison to other scientific means as well as the use of ‘exemplars’…samples of signatures known to be authentic.
Usually the well respected autograph dealer or authenticator you are having check your item will be able to tell whether a signature is a forgery when it is placed side by side with a legitimate signature.
They will generally also check an autograph of roughly the time period when your potential purchase was signed, since penmanship may change if the athlete signed autographs as a younger player and later as retired player with sometimes shaky handwriting.
Your reputable dealer who is an expert in authenticating autographs will analyze the flow, size and structure of each letter in the signature. If you have a program or picture signed, the size is usually somewhat the same. It may differ more on bats, balls or jerseys.
The flow refers to the appearance of the autograph – it should look continuous and smooth, without irregular peaks or edges that are made when someone tries to copy a signature.
A recognized expert will also analyze the structure of the individual letters in a name. The shape and slope of each letter is compared. Some athletes sign their name with a flourish, while others sign more hastily. Your expert may also note whether the way of writing dominant letters is unique and consistent.
When your reputable dealers or collectors are authenticating autographs for you, they may use online samples of hand-writing to compare with your item, as long as they know those selections to be legitimate. In addition, they probably have some of the same autographs in their private collections that they can compare to your item.
Each athlete who signs autographs will have a somewhat personal touch, and your dealer or authenticator can check the similarities and differences between authentic autographs and ones you are interested in purchasing. You may be able to tell the difference if it is very obvious, but it often takes an expert to tell if your autograph is a true find or a clever forgery.