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"Old School" Microdots

  How did microdots originate?

Imagine being able to put a whole document or photographic information onto a 1mm2 microdot. Well it is possible; in fact people were using microdots since World War 2.

Microdots were initially created and used by Nazi spies to pass around information during World War 2. They sent and received top secret information across enemy borders thanks to microdots. Documents were duplicated onto tiny microdots that were not easily visible. The technology was so hi-tech for that time that it took their enemy years to decode these microdots.

The tiny “dot”/ images were put into envelopes, postcards or hidden inside jewellery. Once the microdots were in the hands of the receiver, they would use a special magnifying glass to view the information. These magnifying glasses were also hidden in items such as in a cigarette or pen.

 

 

How did they make their own microdots?

Step 1- Preparation

  1. Develop a photo of either a document, photo or anything you want to put onto a microdot;

  2. Paste a tiny, square piece of damp cellophane onto a glass plate;

  3. Place the photo on the plate as it is now photo-sensitive;

  4. Coat the photo with:

    1. Silver nitrate,

    2. Potassium bromide,

    3. Pyramidone, and

    4. Vodka.

Step 2- Microdot Camera

  1. Use the camera to shrink the text to fit the piece of cellophane- this creates a microdot that in 1mm2.

Step 3- Removing

  1. Take out the cellophane from the glass plate;

  2. Cautiously cut out the microdot.

The person who receives the envelope will need a special microdot viewer to see what information has been put on the microdot.

Image source: www.spymuseum.org