[cctalk] Old fashioned PCB layout images, red/blue

Hi, What is the "correct" name for the style (technology?) of circuit board layout images where the top is blue, the bottom is red and overlaps are purple? Also, any silkscreen is black. I thought someone once told me that there was an automated tool (maybe in KiCad?) that would produce Gerbers from that type of image. Does anyone know of such a utility? Thanks, Bill S. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus