Print jobs from Windows NT clients are enhanced metafiles (EMF). Instead of the RAW printer data being generated by the printer driver, EMF information is generated by the Graphical Device Interface (GDI) before spooling. After the EMF is created, control is returned to the user, and the EMF is interpreted in the background on a 32-bit printing subsystem spooler thread and sent to the printer driver.
EMF files are more portable than RAW files. An EMF file can be printed on any print device, whereas a RAW file can be printed on only one print device model. In addition, the set of EMF files that represent all pages in a print job are typically smaller than a RAW file that contains the same print job.
The first portion of the print job's rendering is done on the client computer. The last portion is rendered on the print server. This is especially helpful when the print job is a very large file, because the client application is not tied up for the entire rendering time. This data type also ensures that fonts specified on the client computer are the same ones used by the print server.