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Blue Noise Mask

A leap forward in halftoning technology – High-quality images in seconds

BNM is the first technology to combine high image quality with high-speed halftone rendering. “Blue noise” refers to an unstructured pattern with small low-frequency-noise components that produces visually appealing arrangements of dots.

BNM provides superior images, free of image artifacts and moiré patterns, at faster speeds.

The benefits of this premier screen include:

  • Quality
  • Speed
  • Color enhancement
  • Simplicity
  • Adjustability

BNM has application in many devices, including ink-jet printers, laser printers, photocopiers, scanners, fax machines and digital cameras.

Download Overview PDF


  • Dr. Kevin Parker, University of Rochester
  • Dr. Theophano Mitsa, University of Rochester

RCT Contact

Christopher P. Martin

Patent Information

Research Corporation Technologies is aggressively licensing its patented halftoning technology, the Blue Noise Mask (BNM).

In 1999, RCT granted printing industry leader Hewlett-Packard Company a license under its BNM patents in settlement of RCT’s infringement lawsuit against HP. In January 2001, RCT and Japan-based Seiko Epson Corporation settled a patent infringement lawsuit RCT brought against Epson in July 2000. RCT granted Lexmark International a license to its BNM patents in 2001 and late in the same year, initiated infringement litigation against Microsoft Corporation. This litigation continues.

With the validation of the commercial benefits and industrial relevance of the BNM, RCT invites current and potential users of this landmark technology to contact us about licenses under RCT’s patent rights.

RCT has developed a formidable portfolio of patents covering this technology, including:

US Patent

  • 5,726,772 (2.8MB)certificate of correction (62KB)
  • 5,708,518 (2.6MB)certificate of correction (22KB)
  • 5,543,941 (1.9MB)certificate of correction (284KB)
  • 5,477,305 (2.3MB)certificate of correction (338KB)
  • 5,341,228 (1.7MB)certificate of correction (167KB)
  • 5,111,310 (845KB)certificate of correction (25KB)

Foreign Patent

  • Japanese Patent JP2622429
  • European Patents EP560872 (1.9MB), EP749232(1.6MB)
  • A third European patent application is allowed and will issue soon. Multiple patent applications are pending in Canada and Ireland.



RCT achieved wide industry acceptance for Blue Noise Mask and has licensed it to a variety of companies that use the software in a broad range of products. View Blue Noise Mask licensing information.