How can you tell if the signature of Lou Gerig and Babe Ruth are real in a photograph?

First thing you should do is determine if the signatures are hand signed or Facsimile signatures. A preprint, or Facsimile signature is simply a photographic copy of an original signed photograph. A Facsimile signature often appears to be below the surface gloss of the photo, and the signature is often very "flat." Hold the photo up at an angle to a light source. A real signature is written on the surface of the photo, and should have a different level of reflectivity than the rest of the surface. A preprint will blend right in with the surface because it's underneath the surface gloss.

If the signatures are hand signed. Find signatures on line that have been properly authenticated, and compare them to yours. If you feel comfortable that they are authentic then proceed to have them authenticated by a reputable company.

An autograph that is not authenticated by a creditable company could sell at half the price or less than one that is. Two of the top, and most trusted authenticators are PSA/DNA, and James Spence Authentic (JSA). Collectors will pay more for signatures authenticated by either one. It may sound odd but in some cases PSA/DNA, and JSA authenticated signatures may sell higher than a Letter of authenticity from an unknown or less trusted authenticator that witnessed the signing even though PSA/DNA, and JSA did not. It's just a matter of collectors trust, and collectors will pay more for it.

Check the respective websites Show Schedule to see if they will be in the area that you live. They also do business through the mail. But before spending money on having the autograph authenticated do your homework, and compare the signatures.

For more information on Facsimile signatures I will leave a link below. I will also leave a link to Babe Ruth, and Lou Gehrig signatures for comparison.