Abstract: A print engine is disclosed comprising a discovery module and a number of content formatters. When a document is to be printed a content formatter is selected based on the format of the document. The document is then analysed together with capabilities data obtained by the discovery module to determine whether the document is in a format compatible with the capabilities of the printer to be used to print the document. If this is the case the unprocessed document is passed to the printer. If the document is not in a format compatible with the capabilities of the printer, the print engine determines whether the document can be modified to remove incompatibilities between the format of the document and a format compatible with the capabilities of the printer without removing content from the document and if so modifies the document and passes the processed document to the printer.