Thirty-five years after its release, Adobe's PostScript Interpreter from a 1991 HP printer cartridge now runs in modern browsers. The retro-ps project emulates the HP C2089A through pagetable.com, allowing users to drop .ps files directly onto a webpage for rendering. This means working with Adobe's own reference implementation—still current as PostScript hasn't changed in decades.

The original cartridge contained Adobe's interpreter (version 2010.118) on a 2MB ROM that plugged into LaserJet printers. retro-ps emulates the Motorola 68000 CPU while faking the printer's mainboard, all processing happening client-side with no server involved. The implementation provides more memory than the original hardware, enabling high-DPI rendering without rewriting the allocator.

The emulator removes original printer constraints, supporting any DPI up to the cart's clip limit and any paper size. Technical improvements include DPI-scaled halftone cells to prevent chalky grayscale fills at higher resolutions. Future work could target other cartridge ROMs like Pacific Page P·E or adapt to later LaserJet models using Intel i960-based processors.