Tamper indicating containers and seals

A seal comprising a transparent or translucent polymeric substrate sheet having a non-sealable outer surface and a sealable inner surface, said sealable inner surface having:

• (a) a transparent masking material disposed in an indicia-defining pattern thereon;
• (b) a colorant layer disposed on the inner surface of the substrate sheet over the transparent masking material and extending beyond the indicia-defining pattern of the masking material;
• (c) a first adhesive disposed over at least the area in which said colorant layer and transparent masking material are disposed;
• (d) a barrier layer disposed over the first adhesive layer opposite the colorant layer;
• and `(e) a second adhesive layer disposed over the barrier layer opposite the first adhesive layer, the second adhesive layer having greater adhesion than the first adhesive layer to the barrier layer;
• said masking material where present reducing the strength of the bond between the colorant and the substrate sheet to below the strength of the bond between the colorant and the first adhesive;
• whereby upon attempted removal of the seal from a surface to which it has been applied, said colorant is dislodged from the substrate sheet within the area defined by the masking material to create a permanent but previously nonevident tamper indicating indicia visible through the transparent or translucent substrate sheet and corresponding to the area defined by the masking material.