Dilip Krishnan and Rob Fergus at New York University have developed a dark or invisible flash which uses infrared and UV light to take photos in dark places without the nasty glare of a standard flash. Their dark flash camera is made by modifying a flashbulb so that it emits light by a wider range of frequencies and filters out the visible light, and removes filters that prevent the silicon image sensor from detecting IR and UV rays. that flash results in a crisp image which does not have exact color balance, and looks like night vision photography. To unmistaken the colors of the image, the camera plus takes a quick color image sans flash right after the dark flash image. The image produced in that second image is predictably grainy and unclear, but the colors are exact. Software is next used to combine the data from the photos to produce the final image (an example of which you see above). There are some minor problems with the method — objects that absorb UV light (such as freckles!) do not show up using that method. The pair will present their work at the Siggraph conference in New Orleans in August.