Authenticating a Longines watch typically begins with verifying the serial number against known production records. The ability to confirm a serial number through Longines' archives is a powerful authentication tool that is not available for all brands. The caliber designation should be consistent with what is known to have been used in the specific model and era.
Movement inspection is commonly emphasized in Longines authentication. Genuine Longines movements typically display characteristic finishing, the Longines name, and the winged hourglass logo. The quality of finishing should be consistent with the model's tier and era. Experienced watchmakers can often assess the authenticity of a Longines movement by examining the construction, decoration, and markings.
Dial authenticity is another important consideration. Genuine Longines dials should feature the correct logo version for the era, clean printing, and proper text formatting. The winged hourglass logo, which has been refined over the decades, should match the known version used during the watch's purported production period. As Longines is a desirable brand with significant collector interest, counterfeiting does occur, and professional authentication is commonly recommended for valuable vintage pieces.