A scalable font technology from Adobe that renders fonts for both the printer and the screen. PostScript fonts come in Type 1 and Type 3 formats. Type 1 fonts use a simple, efficient command language and are widely used, but Type 3 are not. Type 3 fonts can use the entire PostScript language to create complex designs, and Type 3 fonts can also be bitmaps.
Type 1 Fonts
Type 1 fonts are made by Adobe and other companies. They are encrypted and compressed and also allow for hints, which improve the appearance of text at 300 dpi and lower resolutions. With Adobe Type Manager, Type 1 fonts can also be used on non-PostScript printers. However, Mac OS X and Windows, starting with Windows 2000, natively support Type 1 fonts, and Adobe Type Manager is not required.
Type 1 Files (Outlines and Metrics)
Type 1 fonts are distributed as two files, one for the font outlines and another for font metrics (widths, heights, kerning, etc.). Windows uses PFB and PFM extensions for Printer Font Binary and Printer Font Metrics files. See Type 1 font
The Mac uses more general file names; for example, a Helvetica font would have an outline file named "Helve" and a font metrics file named "Helvetica." The icon for the font metrics file looks like a suitcase, and is often called the "suitcase file."
TrueType and OpenType (Type 42)
TrueType fonts and OpenType TrueType fonts are converted to a Type 42 format by the operating system or by the application, as is the case with Adobe applications. OpenType Type 1 fonts are treated just like Adobe Type 1 fonts. See TrueType