In the past year or so, I’ve gotten pretty serious about photography. One of the things I’ve discovered both through my own experimenting, and by reading a number of excellent books on the subject, is that there is this magical device called a “polarizing filter” which, believe it or not, will make a good 95% of your outdoor pictures worlds better, just by slapping it on, and rotating it until the sky turns a deep and magical blue. While just about every photographer knows this little trick, I’d bet they don’t know the history of this incredible device. It’s a tale of war, of invention, and most of all, dog piss.
The polarizing filter was invented by Dr. Edwin Land, of Polaroid fame (hence the name), who had been studying the problem of making a polarizing filter for civil and military applications during his time as a student at Harvard, when he ran across work by Dr. William Herapath whose pupil, one Mr. Phelps, discovered that feeding a dog iodine and quinine caused it’s urine to form strange green crystals which polarized light, called herapathite. Dr. Herapath had spent years trying to grow a single large crystal of herapathite, to no avail, and had given up on the project. Land, inspired by these antics with dog urine, decided to go the opposite direction, and invented a process for forming many small crystals of herapathite, and lining them up properly so they would function as a single large crystal by forcing the, *ahem* crystalizing substance through narrow slits. His experiments were successful, and Harvard invited him back and provided him with space to continue his research.
World War II had several profound effects on Land’s invention. Reflections on the water made it difficult to spot submarines and other naval vessels, thus polarizing sunglasses were used to cut down on the reflected light, making it easier for scouts to spot ships at a distance. However while this increased the demand for polarizing filters, World War II also saw US soldiers coming face to face with the terror of malaria in the South Pacific. Large amounts of quinine were needed to treat these men, limiting the supply for polarizing filters. Land, ever the inventor, took this challenge as an opportunity and developed a new process for creating polarizing filters using sheets of polyvinyl alcohol stretched so as to pull the molecules into alignment.
This new method did not require quinine, and was actually found to create better quality filters than the older iodoquinine sulfate methods, and continued to be the dominate method for producing polarizing filters. Thus died the dog piss polarizer.