Adobe Photoshop is software that is extensively used for raster image editing, graphic design and digital art. It makes use of layering to allow for depth and flexibility in the design and editing process, as well as provide powerful editing tools, that when combined, are capable of just about anything. It was created by brothers Thomas and John Knoll in 1988. In 1989, John sold the program to Adobe Systems, which marketed it as “Photoshop.” Since then, the program has become the de facto industry standard for raster graphics editing. It is published for both macOS and Windows, but not Linux. Advertisement Techopedia Explains Adobe Photoshop Adobe Photoshop was originally developed in 1987 by Thomas and John Knoll, and then Adobe Systems Inc. bought the license to distribute in 1988. Thomas, then in school for his PhD at the University of Michigan, wrote a program on his Macintosh Plus that basically displayed images on a screen and called it Display. His brother John, an employee at industrial Light & Magic, convinced him to make it into a full program. They began to collaborate on it and eventually called it Photoshop, since ImagePro was already taken. They made a short-term deal with Barneyscan, a scanner manufacturer, to distribute copies of the program with a slide scanner they were selling; Photoshop shipped 200 copies this way. John eventually did a demonstration to Apple and Russell Brown, who was then art director at Adobe. Adobe decided to purchase the license to distribute in 1988. Photoshop 1.0 was released on February 19, 1990 and was exclusive for Macintosh. Each Photoshop release improved upon the last, and it quickly became the standard in digital photo editing. Photoshop is specifically designed to allow users to create and edit raster images in multiple layers. These overlays or layers can support transparency and can also act as masks or filters that can alter underlying images in the layers below them. Shadows and other effects such as alpha compositing can be applied. It is also possible of apply several color models to these layers – CMYK, RGB, Spot Color, and Duotone and Lap color space. The default file extension for a work in progress is called .PSD (Photoshop Document). A PSD file has a maximum of 30,000 pixels for width and height and a file length limit of 2 gigabytes. Another type of Photoshop file is .PSB (Photoshop Big) – it is a large document format and extends the PSD’s maximum height and width limit to 300,000 pixels and also extends the length limit to around 4 exabytes.