PART IV. Die Errors:

Die Deterioration / Deformation errors: 

Die Deterioration Doubling:

Incuse doubling

Definition: Die deterioration (die wear, die fatigue) sometimes produces discernible doubling of affected design elements.  We call this die deterioration doubling (DDD).  Its appearance is highly variable.  It is often raised but can sometimes be incuse.  Incuse DDD is most often seen on copper-plated zinc cents, but does occasionally appear in other issues.  Die deterioration doubling may completely surround an affected design element (like a number or letter) or may be restricted to one side.

Unusual forms of die deterioration and die deterioration doubling often develop on dies that strike zinc cents. Illustrated above is a 1989-D Lincoln cent exhibits swelling of the field on both sides of Lincoln’s bust and the development of a low ridge (“ridge ring”) that runs through in god we trust. The date shows a form of incuse die deterioration doubling that is common on zinc cents but rare on other denominations.

Below are two views of another 1989-D Lincoln cent with incuse DDD, and to the right a 1993 Lincoln cent with incuse DDD above EPU. While altogether different, incuse DDD can visually seem similar to, plating disturbance doubling. While plating disturbance doubling is raised, and the form of DDD illustrated incuse, they often inhabit the same regions of Lincoln cents and seem similar under certain lighting conditions.

Below are images on incuse DDD on a 2007 Idaho State Quarter.