Twenty years ago Adobe has published the PostScript Language Reference Third Edition, better known as «PostScript 3» (without «Level»):
These were the most important new features of PostScript 3:
- 4096 gray levels for each color (was 256) allowed smooth shades and improved screening.
- DeviceN color definitions enabled among other things duotone images and spot color gradients.
- Smooth shades.
- Image masks.
- Two byte fonts (CID).
- New font types: e.g. CFF, TrueType.
- ZIP compression/decompression (Flate).
- InRIP trapping.
- Color Rendering Intents.
- PS3 RIPs could convert PDF 1.3 to PostScript.
PostScript 3 was the last update of PostScript with new features. Further developments (e.g. transparency, layers) were all reserved for PDF and no longer compatible with PostScript.