X

Photoshop 1.0 source code now a museum artifact

The technocurious now can peruse the inner workings of Adobe's first version of the famed image-editing software, written in Pascal and assembly code and released in 1990.

Stephen Shankland Former Principal Writer
Stephen Shankland worked at CNET from 1998 to 2024 and wrote about processors, digital photography, AI, quantum computing, computer science, materials science, supercomputers, drones, browsers, 3D printing, USB, and new computing technology in general. He has a soft spot in his heart for standards groups and I/O interfaces. His first big scoop was about radioactive cat poop.
Expertise Processors, semiconductors, web browsers, quantum computing, supercomputers, AI, 3D printing, drones, computer science, physics, programming, materials science, USB, UWB, Android, digital photography, science. Credentials
  • Shankland covered the tech industry for more than 25 years and was a science writer for five years before that. He has deep expertise in microprocessors, digital photography, computer hardware and software, internet standards, web technology, and more.
Stephen Shankland
2 min read
The Photoshop 1.0 splash screen
The Photoshop 1.0 splash screen Computer History Museum

The Computer History Museum has made the source code for Photoshop 1.0.1 into an exhibit that lets the public, or at least programmers, appreciate the inner workings of the historic software.

The museum published the software yesterday, following up on its earlier release of the source code underlying Apple's original MacPaint.

Source code is what humans write -- in Photoshop 1.0's case the brothers Thomas and John Knoll. The initial Photoshop is written in written 128,000 lines of code, a combination of the high-level Pascal programming language and low-level assembly-language instructions. When converted to machine code, the program was small enough to fit on a floppy disk.

Photoshop started in the 1980s as a personal project the brothers called Display, but they started trying to commercialize it, according to the museum's exhibit. Their first success was version 0.87, which scanner maker Barneyscan called Barneyscan XP, but Adobe Systems agreed to a deal in 1989 and distributed Photohshop 1.0.1 in 1990.

Photoshop 1.0.1 dates from a time when many computer screens were small and could display only black or white pixels -- not even gray. And of course image processing is very taxing for computer chips. Although today's large, color monitors are very different, Photoshop still pushes computer processors about as hard as they'll go.

The museum also published the Photoshop 1.0 user guide and tutorial documentation.

Of course, new types of museum exhibits mean things change for those perusing the exhibits, too. In this case, it's a 1,400-word license agreement to see the Photoshop source.

Photoshop 1.0 in action
Photoshop 1.0 in action Creative Bits and the Computer History Museum