To See Within: Detecting X-Rays

It’s amazing how quickly medical science made radiography one of its main diagnostic tools. Medicine had barely emerged from its Dark Age of bloodletting and the four humours when X-rays were discovered, and the realization that the internal structure of our bodies could cast shadows of this mysterious “X-Light” opened up diagnostic possibilities that went far beyond the educated guesswork and exploratory surgery doctors had relied on for centuries.

The problem is, X-rays are one of those things that you can’t see, feel, or smell, at least mostly; X-rays cause visible artifacts in some people’s eyes, and the pencil-thin beam of a CT scanner can create a distinct smell of ozone when it passes through the nasal cavity — ask me how I know. But to be diagnostically useful, the varying intensities created by X-rays passing through living tissue need to be translated into an image. We’ve already looked at how X-rays are produced, so now it’s time to take a look at how X-rays are detected and turned into medical miracles.

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Mix Your Own Photo Developing Emulsions

If you’re into developing your own photographs you might try mixing your own emulsion. [Jimmy Hartnett] worked out the chemical reaction necessary to make a photosensitive medium using Silver Chloride. His process lets him manufacture canvas that can be use like photo paper. The gist of it involves coating the back of a canvas with Gesso to prevent the emulsion from passing all the way through. He then floats the canvas face-down to apply the emulsion and skims it with a straight edge before it has time to set. You can see the results of some contact print testing in the image above. If anything, this makes a great piece of art to hang on the wall as it’s visually interesting and [Jimmy] has a personal connection because he not only made it himself, but came up with the process.