What is a CPC file?
CPC (Cartesian Perceptual Compression) is a proprietary image file format that uses the .cpc extension for its files. CPC was designed for high compression black-and-white archival scans. CPC is a lossy file format and is restricted by bi-tonal images. CPC is intended for web distribution of legal documents, design plans, and geographical plot maps.
JSTOR converted its online archives to CPC in 1997. JSTOR converts CPC on their servers to GIF for display and to PDF for printing. CPC files are used to reduce the amount of storage used by the online collection.