HP Indigo presses have received a Wilhelm Imaging Research (WIR) display permanence rating of approximately 45 years, the first of its kind for a digital press, said the company.

　　The study gives pages printed with HP Indigo presses on a Kromekote paper from Smart Papers a WIR display permanence rating that is longer than the best-rated silver-halide photo paper, Fuji Crystal Archive, said HP.

　　The Indigo presses' rating is also more than twice as long as the WIR display permanence rating for prints on Kodak silver halide photo paper.

　　Indigo photo book prints received a WIR album and dark storage rating of greater than 100 years.

　　Henry Wilhelm, co-founder, president and director of research at Wilhelm Imaging Research, said: 'The permanence ratings from WIR provide an important validation for the use of HP Indigo presses in consumer and professional photographic markets, as well as in the fine art world.

　　Good display permanence combined with excellent long-term stability, as well as freedom from yellowing for images that are in albums or are stored in other dark locations, are essential to preserving the value of historical photographs, art works and photo books.