Abstract: In the automatic processing of documents having bar encoded printing thereon, selectively variable error detection and correction codes are added to a bar encoded data field. Read errors which may occur from the reading of document data fields having overprints of inks of various types, colors and densities thereby may be substantially reduced. More particularly, either, neither or both a random parity code and a Bose-Chaudhuri-Hocquenghem (BCH) code may be added to a data message for a bar code printing to accommodate error correction and detection systems having differing processing capabilities. Further, the BCH code may be dynamically and selectively altered to accommodate both documents and data fields of varying lengths.