Additional filters are specified in files with the extension .convs in the CUPS configuration directory.
Each line in the mime.convs file is a comment, blank, or filter line. Comment lines start with the # character. Filter lines specify the source and destination MIME types along with a relative cost associated with the filter and the filter to run:
source/type destination/type cost filter
The source/type field specifies the source MIME media type that is consumed by the filter.
The destination/type field specifies the destination MIME media type that is produced by the filter.
The cost field specifies the relative cost for running the filter. A value of 100 means that the filter uses a large amount of resources while a value of 0 means that the filter uses very few resources.
The filter field specifies the filter program filename. Filenames are relative to the CUPS filter directory.
application/vnd.cups-postscript application/vnd.cups-raster 50 pstoraster