Convert CALS to PBM

The CALS (Continuous Acquisition and Life-cycle Support) Type 1 Image file format, developed by the United States Department of Defense in the mid-1980s, is a standard for storing raster (bit-mapped) image data, typically black-and-white. It ensures efficient data interchange and retention of orientation metadata. The format supports both uncompressed and compressed (using CCITT Group 4 compression) images. This standard was part of the broader CALS initiative aimed at improving electronic publishing and data management within the federal government.

The PBM (Portable Bitmap) file extension, part of the Netpbm project, originated in the late 1980s to facilitate efficient and portable graphics file interchange. Primarily, PBM files are used to store monochrome bitmaps in a simple ASCII text format, ensuring easy compatibility across different systems and platforms. This format supports only black-and-white imagery, making it particularly useful in scenarios where simplicity and minimalism are prioritized, such as in Unix environments for bitmap manipulation and transfer. Its historical significance lies in promoting a standardized approach to bitmap graphics in early computer technology.