Convert PostScript to PPM / PNM

PostScript (PS) is a dynamically typed, concatenative page description language developed by Adobe Systems, serving as the predecessor to the PDF format. It describes text and graphics on a page using vector graphics instructions rather than rasterized pixels, making it resolution-independent. A PS file contains a program written in the PostScript language, which is interpreted by a Raster Image Processor (RIP) to generate the print output. It supports distinct imaging models, including Type 1 fonts and color separations, and became the standard for desktop publishing and high-end printing workflows in the 1980s and 90s.

Opening PS files requires software capable of interpreting the PostScript language, as modern OS image viewers do not support it natively. Ghostscript is the standard open-source interpreter used to view and convert PS files. For GUI-based editing and viewing, Adobe Illustrator and CorelDRAW can import PS files. Users can also convert PS files to PDF using tools like ps2pdf (part of the Ghostscript suite) for easier accessibility.

The Portable Pixel Map (PPM) format is a lowest-common-denominator color image format developed by Jef Poskanzer as part of the Netpbm project. It stores pixels as uncompressed RGB triplets (Red, Green, Blue) in either a plain ASCII text format (P3 header) or a more efficient binary format (P6 header). The file structure is extremely minimal, consisting of a magic number identifier, dimensions (width and height), maximum color value, and the pixel data itself, making it easily parsable by simple scripts but inefficient for storage compared to compressed formats like JPEG or PNG.

Native support for PPM files is absent in standard Windows or macOS photo viewers. Users typically require specialized image manipulation software to view or convert these files. GIMP (GNU Image Manipulation Program) and IrfanView are the primary tools for opening PPM files on desktop environments. On Linux systems, the Netpbm toolkit and ImageMagick suite provide command-line utilities for processing and converting PPM data.