Type 1 fonts (also known as PostScript, PS1, T1, Adobe Type 1, Multiple Master, or MM) are a deprecated format within the font industry, replaced by the larger glyph sets and more robust technical possibilities of OpenType format fonts.
Type 1 fonts were introduced by Adobe in 1984 for use with its PostScript page description language, and became widely used with the spread of desktop publishing software and printers that could use PostScript. In 1996, Adobe products and type development began to concentrate on the use of more versatile OpenType fonts rather than Type 1.
While the use of Type 1 fonts is still supported by some operating systems, it is not supported in many environments crucial to modern platforms, including web browsers and mobile OSes. The lack of support for Unicode information in Type 1 fonts also limits their ability to support extended language character sets.
Users will no longer have the ability to author content using Type 1 fonts beginning January 2023. Until that time, users will be able to work with their Type1 fonts without any change.
Some products, including Document Cloud applications, will continue to display and work with Type 1 fonts as they have all along.
Photoshop will end support for Type 1 fonts in 2021, as announced in 2019. See the Photoshop announcement for more information.
Adobe applications will not recognize the presence of Type 1 fonts, even if you have Type 1 fonts installed in your desktop operating system:
1. Type1 fonts will not appear in the Fonts menu.
2. There would be no way to use previously installed Type1 fonts.
3. Existing Type1 fonts will appear as “Missing fonts” in the document.