Convert PDF to PGM

.pdf

Adobe Viewer

PDF – is a cross-platform extension necessary for the visualization of printed materials in electronic form. It is developed by Adobe Systems using separate PostScript resources. PDF documents can exist separately from the OS or hardware tools with which they were developed. Files of this format do not have restrictions on the length, several types, and image options, as they allow you to embed various multimedia tools, scan-line, and vector images. They are supported by Adobe Reader and many browsers, providing the plugin is installed.

PDF supports color models CMYK, RGB, shades of gray, and also it has its technical formats for performing the exchange of finished documents. Any file contains a description of a 2D or 3D document with all the necessary components (scan-line, vector graphics, text, and more). The extension does not encode data associated with the software or OS used to develop and view it.

Adobe Systems

.pgm

PGM file format was developed alongside the open-source Netpbm package of graphics program. Developed by Jef Poskanzer in 1988, PGM was a format for storing grayscale images and supporting bitmap. The PGM file format is forward compatible with recent graphics editing software like Corel PaintShop Pro X4, ACDSee Photo Manager 14, and ACD Systems Canvas 15. Being a plain text format, PGM can be edited using any available text editor, and thus survives the quintessential changes that image files undergo when transmitted via email. PGM files come in two types, only differentiated by magic numbers – P2 and P5, which helps graphics editor software identify the data encryption standard.

Portable Gray Map Images can be stored away with each pixel taking up memory space of either 8 or 16 bits. There are two major sections in the plain text string of a PGM file – the header and image data. The header starts with the magic number, followed by characters indicating image width, image height, maximum grayscale shade value – never exceeding 65.536, all sandwiched by whitespaces. Though used mainly on the UNIX-based operating system, being open-source has earned the PGM file compatibility with macOS and Windows.

Jef Poskanzer