A Developing Process Sped by an Accidental Discovery
By tradition, in continually improving the photographic developing process Daguerre once casually stored a batch of underexposed, seemingly failed plates in a cabinet holding the residual mercury of a broken thermometer, and days later, taking them out to look, was astonished to find clear images had appeared on these plates — from which he realized mercury vapor had the unique chemical action of speeding development, and this accidental discovery was thereafter systematically integrated into the complete photographic process he at last publicly released.
The French Government Bought the Patent and Released It Free
After Daguerre developed practical photography, the French government, recognizing the far-reaching value of this invention to science, art, and the way society records itself, actively paid to buy out the daguerreotype patent and then released the technology completely, allowing anyone in the world to use it free without paying a licensing fee — this rare handling of "government buyout then free release" greatly sped the swift spread of photography across Europe and America, and this precedent was later often seen as a viable model for handling technological inventions of great public value.