What are Multiple Master Fonts?
Adobe has modified ATM and PostScript interperters slightly to use an extension on the Type 1 font format. This extension allows multimaster or MM fonts. These are a parameterized Type 1 font in which some font attributes are dynamically adjustable before rendering by ATM. For example, one parameter might be the face weight (light to Demi to Bold, etc.) and another might be the character width. Using MM fonts, only one Type 1 font description needs to be downloaded to the printer and when different fonts realizations are needed, only the parameters need to be specified in the PostScript file. The MM code in the printer then renders a new realization of the font in the printer.