Browse Prior Art Database

Automatic performance vs. image quality trade-off for direct PDF printing

IP.com Disclosure Number: IPCOM000237513D
Publication Date: 2014-Jun-19
Document File: 2 page(s) / 50K

Publishing Venue

The IP.com Prior Art Database

Abstract

Most Multifunction Devices (MFD’s) are capable of printing Portable Document Format (PDF) documents. Frequently this is done through the use of Adobe’s PDF to PostScript (PS) conversion technology. A PDF file can be submitted for printing using many methods such as from a Universal Serial Bus (USB) thumb drive. During conversion and processing, documents are usually “flattened”, which can be a very slow and memory intensive process. This idea proposes a process to modify the “flattening” parameter used to speed up the processing at the expense of degrading the image quality of the printed document. This tradeoff may be acceptable to the end user of the MFP due to the reduction in time required.

This text was extracted from a Microsoft Word document.
This is the abbreviated version, containing approximately 52% of the total text.

Automatic performance vs. image quality trade-off for direct PDF printing

Most Multifunction Devices (MFD’s) are capable of printing Portable Document Format (PDF) documents.  Frequently this is done through the use of Adobe’s PDF to PostScript (PS) conversion technology.  A PDF file can be submitted for printing using many methods such as from a Universal Serial Bus (USB) thumb drive.  During conversion and processing, documents are usually “flattened”, which can be a very slow and memory intensive process.  This idea proposes a process to modify the “flattening” parameter used to speed up the processing at the expense of degrading the image quality of the printed document.  This tradeoff may be acceptable to the end user of the MFP due to the reduction in time required.

Typically, the PDF file is copied to the MFP’s hard disk and then sent to the PDF to PS converter.  The output from the converter is piped to the PostScript interpreter, and the resulting images are passed down to the print engine for subsequent printing. 

An increasing number of PDF files contain “transparency” and include layers of objects, some of which are wholly or partly transparent. The PostScript imaging model does not support transparency, meaning that these “transparency stacks” need to be “flattened” to opaque images in the PDF to PS conversion process. Not all PDFs contain transparency, and most that do can be processed quickly. However, flattening some complex PDF files can sometimes be very slow and very memory-intensive. On rare occasions, it can take hours to process a single page.  Adobe provides a “flattening level” parameter for use with its PDF to PS converter. This parameter affects the image quality of transparent objects on the printed pages. It has 5 possible settings.  Level 5, the default, provides the best image quality, but tends to have the worst performance.  Level 1 provides the lowest quality, but at a higher speed. Many of the PDF files that take a long time to process at level 5 can be handled in just a few seconds at level 1. Level 1 “cheats”, by (e.g.) down-sampling images to less than their full resolution.

End users submitting PDF jobs for printing could be exposed to this flattening level parameter by making this a user configurable parameter for the printer.  But this “all or nothing” solution would be far from perfect. The flattening level adjustment really needs to be made on a job by job basis and the current default of level 5 works just fine for the majority of jobs.  It would not be a good scenario to allow users to set the parameter for the benefit of a handful of complex files if it means compromising the image quality on the rest of their print jobs. Ideally, the determination of the...