Existing comment:
Dot-size Documents:
A microdot is a photograph so small, an entire document can be reduced to the size of a punctuation mark in a newspaper. Originally developed as a parlor trick, microdots became essential tools of the spy craft trade.
These tiny images could be embedded on an envelope or postcard, or hidden inside a ring of cufflinks. Reading them required special magnifying viewers. Often, these too were cleverly concealed in a cigarette or a fountain pen. |