From the viewpoint of an outside observer - i.e., us - it would look like the black hole was giving off a steady stream of radiation.
How fast it evaporates depends on the black hole's size: the smaller it is, the faster it evaporates. Ergo, for those who might be worried, even in the event that the Large Hadron Collider in Switzerland really does produce mini black holes, they would be roughly the size of an electron, and would evaporate in mere fractions of a second. They would not gobble up the universe, no matter how many frivolous lawsuits are filed claiming the contrary.
Oh, but scientists can't be 100% certain of that, the fear mongers still claim, because they have yet to observe bona fide Hawking radiation in the actual universe. That's where the analogue black holes come in: these arise from lab experiments that use sound or light waves, for example, to imitate the physical properties of the event horizon, the point of no return for any object unfortunate enough to cross that invisible line.