This repository is a how-to for creating a film microdot using "The British Method" of microdot production.
Modern microdots have been used in both armed and unarmed conflict over the past century as a way to secretly transmit information from one place to another. Famously, this technique was used by Adolf Tolkachev, an American asset working in the Soviet Union until his capture in the 1980s.
The value of microdots is in their size. Since they are very small, they can be clandestinely transported from one place to another and can contain incredible amounts of information on a microscopic piece of film.
There are a number of limitations to recreating an authentic film microdot that make it an impractical data transfer system with modern technology options.
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"High latency, low bandwidth". Imaging a single page at a time is time consuming and yields a relatively small amount of information per page.
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Film development is not conveniently available in the digital age. At least, not in the United States. Film can be developed rapidly with online services, but it's not as easy as it once was.
Why would I do this? It's not the most practical thing in the world to do considering the limitations. As both a student of history and a technologist, I recognize the value of remembering the functionality of old, obsolete technogies.
This is a long, stuck up way of saying, "I felt like it and I could."
In this explainer, I will be covering two different methods for microdot production, and a third hybrid system that can bridge analog and digital formats.
The one step method will produce a 2cm X 1cm "macrodot" that will hold one full-page document of information per dot.
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35mm camera
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high contrast B&W 35mm film
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original document to miniaturize
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scissors/cutting board
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Begin by placing your document in an unobscuted area, preferably one that is well lit and will give you a direct line of sight to the document from roughly 10ft away from the sheet of paper. To do this, I placed the original document on the ground, and stood on my kitchen counter.
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Frame up the image by adjusting the lens so that the document fills the entire field of view when you look through the viewfinder.
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The image needs to be fully in focus when you take the photo. This means that if you usually wear glasses, you need to wear the glasses when you take the photo. If the image isn't in focus, then the microdot will not be very useful.
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Once you have recorded all of the documents that need to be minaturized to the film, have the negatives developed.
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When the negatives come back, you will need to cut the film to size. Use scissors or an xacto-knife to crop out any negative material that does not contain the document.
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What you end up with should be close to a 2cm in length "macrodot" that is still readable with the naked eye, but also small enough to be concealed almost anywhere without raising suspicion.
The 2-phase method builds on what has already been accomplished in the 1-phase method. So whether you intend to end up with a 2x1cm microdot or not, you will have this at the start of the 2-phase method. What we will end up with at the end of the 2-phase method is a microdot that is 1mm in length. Literally a spec of dust, that will be readable with the aid of a microscope or other magnifying device.
If a microscope isn't handy, a high-powered magnifying glass may come in handy, but an even cheaper solution is to go into a souvenir shop and buy one of those cute tiny grains of rice with the constitution written on it or whatever. Throw out the piece of rice, because fuck that shit, and put the microdot into the little box instead.
This should be sufficient magnification to see the microdot.
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35mm camera
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high contrast B&W 35mm film
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original document to miniaturize
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scissors/xacto-knife & cutting board
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dark colored/Black mounting board (foam insulated board is preferable if you can find it.)
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Starting with either a 2cm or larger negative of the original document taken in the first phase, take the black mounting board and cut a space out of the middle of the board. If you were able to get foam insulated board, make sure the cut goes all the way through the board so that light can pass through it.
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Put the negative into the window cut into the mounting board. This is where the foalm insulated board comes in handy. The insulation will create a small pocket that the negative will easily fit into and will be held in place without the need for any tape.
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Place the mounting board in front of a light source. The idea here is to backlight the negative so that it's visible from the other side of the mounting board. In this image, I put my mounting board against a lamp and held it in place with a piece of tape.
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Load the second roll of 35mm film into the camera and line up the shot of the backlit negative in the viewfinder.
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Don't stand any more than 4ft. away from the mounting board, and again, make sure that the negative is in focus. This will be difficult because the text on the negative will be so small that it will probably be hard to tell if the text is in focus.
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Have the negatives developed once again.
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When the negatives come back, repeat the same cutting steps from the 1-phase production method.
Once the microdot has been created, finding a way to transport it is the next big challenge. Depending on whether you've made a 2cm dot, or a literal piece of dust, your options will be a little different.
Historically, stamps have been a popular way of hiding microdots. In the good old days, people used to do all kinds of things to stamps in order to hide both information and drugs. In the case of microdots, placing one under a stamp, fixing the stamp to an envelope, and mailing it to a recipient who has been told ahead of time that the stamp conceals a microdot was an effective way of moving illicit information from one place to another using the mail system.
This was convenient in pre-internet days, but could still be used as an alternate method of data transfer for more modern information.
Digital microdots haven't been much explored because of other digital options that are often much more efficient in data obfuscation than image minaturization. On the other hand, an overlooked method of data transfer is a spy's best friend. So what are the options?
One option is to use simple tricks like white text on white background. Another cheap trick is to simply make a borderless white box that can cover hidden information. Neither ensures security of the information being hidden, but this is only meant to be one tool in a set of tools.
These are both basic-bitch methods that are likely to get you caught quickly, and aren't good options in general for serious information transfer needs. But what about some other choices?
Trying to duplicate the film-stock microdot production method with a digital SLR would result in a high-resolution image file which could hypothetically be used to convey a microdot image. This would make the transfer of data much easier using digital technology, but as has been pointed out elsewhere, wouldn't make as much sense considering the variety of other, better digital information transfer options.
However, illicit data transfer using this hybridized digital microdot method would certainly be a novel way of moving information from one place to another, and thus shouldn't be immediately counted out.
RFID microdotting is an underappreciated technique for physical data transfer. This has a number of low-cost, effective appliations that have not yet been developed.
RFID stickers are so small, cheap, and ubiquitous that I included an encoded RFID sticker in the first issue of The Teletypist a year ago. Most people I handed a physical copy to didn't realize that there was a sticker pasted inside the pages to begin with, and fewer still made any attempt to recover the information off of the chip inside. It seems that the RFID sticker idea was a victim of its own success.
But what of some other models of illicit information transfer that rely on a more sneakernet based solution? When electronic means of data transfer become unreliable or untrustworthy, a simple system of loading data onto an RFID card and instructing the courier to tap it against a covertly placed reader at a safe location would provide a smooth and clandestine way of transfering small amounts of data without compromising either endpoint in the transfer.
The reason we can only produce true microdots with older photographic techniques is due to the way film works. With enough focal length, a reproduction of any size big or small can be made from a 35mm negative. As digital technology improves, higher resolution photos may open up more avenues for covert placement of human readable information in the field of an image become possible.
For example, a microdot held between the fingers as we see here can be saved as a smaller resolution image, but once clicked can display a full resolution image making the text on the negative readable. The difficulty in this method is that the dot will need to be in focus, which will likely impact the focus of the rest of the image.
Is that a grainy image, or a photo covered in tiny microdots? It's hard to tell, but not hard to imagine that a grainy quality in an image could house tiny fragments of human readable information. This is just a concept, so don't ask me for a PoC. I don't have one.
After having produced something like this, it's easy to wonder why this method was ever used for info transfer. We've had radio communications for virtually as long as we've had microdots, so the applicability of this method might seem odd to the laymen.
The historic reality is that microdots have a time and place. What that time and place is, is up to the sender and recipient. While there are enough back-alleys that still exist on the Internet, there are still places on the planet where it's less risky to use a more rudimentary, older system.
For me, this process could be improved by using a higher quality of film stock. What I used was a fairly standard roll of 35mm film, but something much higher in contrast such as microfiche or other stock specifically designed for high-quality document photography would have worked much better. Another possible improvement for next time would be to use a lens with a better focal distance than what I had at my disposal. This will be a bit harder to work around since these kinds of lenses are typically much more expensive.
If I could only choose one thing of the two to improve the quality of the smallest size of microdot for next time though, it would be the higher film stock.
Are microdots an anacronism that have no application in the modern world? Has their time long since passed, and died with the Cold War? It's hard to say. I can imagine some far off applications that this methodology could be used in today, but the limitations can be hard to overcome.
Some readers may decide that microdots are a silly novelty that don't have any more operational life left in them. On the other hand, consider that the idea of a shortwave radio broadcast reading one-time-pad numbers in 2020 still has operational viability.
Whether this experiment is a novelty or a truly applicable method of data transfer in the 21st century is up to the user to decide.