Convert CAL to G4

The CAL file extension, known as CALS (Continuous Acquisition and Life-cycle Support) Type 1 Image, is a 1-bit black-and-white raster image format developed by the U.S. Department of Defense in the mid-1980s to standardize graphics data interchange for military documentation. It is primarily used for storing and sharing monochrome images while retaining orientation metadata. The format supports both uncompressed and compressed (using CCITT Group 4 compression) images.

The G4 file extension, standing for CCITT Group 4 Fax Image, is a specialized format used primarily for storing black-and-white facsimile (fax) images. Its origins trace back to the Consultative Committee for International Telegraphy and Telephony (CCITT), now known as the ITU-T, which developed the Group 4 standard in the 1980s to improve fax transmission efficiency over digital networks. This format employs a high compression ratio to reduce file size while maintaining image quality, making it ideal for archiving documents and transmitting faxes in professional and business environments.