Adobe releases source code for 1990 version of Photoshop

All 128,000 lines of code for the first version of the pioneering software released 23 years ago are available for free download from the Computer History Museum.

Packaging and floppy for the original version of Photoshop. Computer History Museum

How would you like to download a free and legal version of Photoshop?

Yep, free and legal. Better yet, it's an original -- as in the original version (1.0.1) that was released in 1990.

Via a special arrangement with Adobe Systems, the Computer History Museum announced in a blog post today that it has made available for download the entire 128,000 lines of source code for the first version of Photoshop:

All the code is here with the exception of the MacApp applications library that was licensed from Apple. There are 179 files in the zipped folder, comprising about 128,000 lines of mostly uncommented but well-structured code. By line count, about 75% of the code is in Pascal, about 15% is in 68000 assembler language, and the rest is data of various sorts.

The vast majority of that original source code was written by Photoshop co-founder Thomas Knoll. For the second version, Knoll took on a second engineer.

Knoll, a computer vision Ph.D. student at the University of Michigan, created the program, then known as Display, on his Apple Macintosh in 1987. His brother John, an employee at movie visual effects company Industrial Light & Magic, found the program useful for displaying and modifying gray scale digital images.

Originally created mostly for personal use, the program gradually became more sophisticated, leading the brothers to believe they had a viable commercial product. After renaming it Photoshop and distributing about 200 copies of version 0.87 bundled with a slide scanner, the Knolls sold their program to Adobe in 1989 and version 1.0 was released in 1990 exclusively for Macintosh.

Screenshots of that first version:

Photoshop's home screen, showing the available tools. Computer History Museum

Photoshop allowed users to select brush color as well as size and texture. Computer History Museum
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