Photoshop, home of the PSD document format, started life back in the late eighties when PhD student was working on his thesis--a work detailing the processing of digital images. What started as a thesis soon evolved and in 1987 Thomas got to work on writing an image processing program for his Mac. His creation was created to work with grayscale images, and over a short period of time Thomas developed his program further, adding to it new digital editing processes. It didn't take long before his brother John Knoll was intrigued by the program, dubbed Display.

John, who was working at George Lucas' Industrial Sound & Magic, . From here the two worked together, combining Thomas' engineering background with his brothers design experience.

By 1988 the program had changed dramatically, with a whole host of new features and a name change to ImagePro. This name change --the brothers decided to give the project another six months, complete a beta and attempt to sell it commercially with the help of the big guys in Silicon Valley.

One company decided to give the now Photoshop a go, but it wasn't Adobe. A company called BarneyScan were the first to take to the brothers software, deciding to include around 200 licensed copies of the program with their scanners. However, it wasn't long before Adobe did see the potential that Photoshop offered. In September of 1988 John gave a presentation to Adobe's internal creative team, and the rest is history.