A PostScript font, also known as a Type 1 font, has two parts. One part contains the information to display the font on screen and the other part is for printing. When PostScript fonts are delivered to printers, both versions (print and screen) must be provided.
PostScript fonts allow for high-quality, high-resolution printing. They were developed by Adobe and for a long time considered the professional's choice for printing. PostScript font files are not cross-platform compatible, meaning different versions exist for the Mac and PC.
PostScript fonts have widely been replaced, first by TrueType and then by OpenType fonts. While TrueType fonts worked well alongside PostScript (with TrueType ruling the screen and PostScript ruling print), OpenType fonts combined many of the best features of both and have become a leading format.