Most of us are relatively familiar with the history of photography in the last decade or so, but I'd argue its early years were far more interesting, with patent wars abounding and chemicals making people crazy (ok, maybe I'm glad that part is no longer an issue). This fascinating documentary details the history of early photographic processes, their development, and the stories of the people behind them.
If you're old enough to remember when digital cameras really took hold from film, you likely remember the astoundingly exponential rate that they developed at, with manufacturers leap-frogging one another in quality and capabilities seemingly every few months. The birth of photography as a visual medium was much the same: once the viability of the process was clear (and more importantly, its economic potential was apparent), inventors raced to improve it. This became particularly important when the processes became both of a high enough quality and quick enough to make human portraits possible and again when they became simple and cheap enough to put cameras in the hands of the average person. This great documentary will take you through those exciting periods in the 19th century and into the 20th century; I definitely recommend sitting down with it this evening.