PCL 6 was introduced around 1995, and consists of:
|PCL 6 Enhanced: An object-oriented PDL optimized for printing from GUI interfaces such as Windows and compressed to optimize throughput. Formerly known as PCL XL.|
|PCL 6 Standard: Equivalent to PCL 5e or PCL 5c, intended to provide backward compatibility.|
|Font synthesis: Provides scalable fonts, font management and storage of forms and fonts.|
PCL 6 Enhanced features new modular architecture that can be easily modified for future HP printers; faster return to application; faster printing of complex graphics; more efficient data streams for reduced network traffic; better WYSIWYG printing; improved print quality; truer document fidelity; and complete backward compatibility. In early implementation, HP did not market PCL 6 well, thus causing quite a bit of confusion in terminology. PCL XL was renamed to PCL 6 Enhanced, but many third party products still use the older term. Some products may claim to be PCL 6 compliant, but may not include the PCL 5 backward compatibility. PCL 6 Enhanced is primarily generated by the printer drivers under Windows and CUPS. Due to its structure and compression methodology, it is rarely used by custom applications.
PCL 6 Enhanced is a stack-based, object-oriented protocol, similar to PostScript. It however is restricted to binary encoding as opposed to PostScript, which can be sent either as binary code or as plain text. The plain-text commands and code examples shown in the PCL programming documentation are meant to be compiled with a utlity like HP's JetASM before being sent to printer. Perhaps because PCL 6 is designed for small size, operators are not as flexible or orthogonal as PostScript.
PCL 6 Enhanced is designed to match the drawing model of Windows GDI. In this way, the Windows printer driver simply passes through GDI commands with very little modification, leading to faster return-to-application times. Microsoft has extended this concept with its next-generation XPS format, and printer implementations of XPS are being developed. This is not a new idea: it is comparable with Display Postscript and Apple's Quartz, and is in contrast to "GDI Printers" which send the printer a compressed bitmap.