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PPM file format

File extension
.ppm
File category
Description
Portable pixmap images can be stored using the PPM format which is basic for example color (PPM), gray scale (PGM) and the black and white (PBM). Portable pixmap can provide a hallway representation of information in the conversion process of bitmap image files of the three types that are mentioned between different platforms. PPM format was developed by Jeff Poskanzerom.
Technical details
PPM files comprise sequences of a single or more PPM images. Data, padding and limits do not exist prior to or after or in the middle of images. Every PPM comprises of a single magic number used in the identification of the type of file; the magic number for a PPM image is the two character P6, whitespace (blanks, TABs, CRs, and LFs), and a width presented as ASCII characters in decimal. It also comprises a whitespace again which is presented in ASCII decimal. A whitespace, the color value at a maximum (Maxval) which is in decimal form and it should be greater than zero but less than 65536. It is also composed of another single whitespace character which most of the time is on another line. Lastly, it is composed of a raster of height rows which is found in reverse chronological order. The rows are comprised of width pixels in a left to right format. The samples represented have a pure binary nature which is by one or two bytes. I byte has a Maxval of less than 256 otherwise, it is 2 bytes. The first byte is the most relevant. The plain format is another version of the PPM exists but is mostly uncommon.
Programs
Adobe Photoshop
Corel Draw
GIMP
Netpbm
Developer
Jef Poskanzer
MIME type
image/x-ppm
image/x?portable?pixmap