US image assessment and quality body Image Test Labs has declared that its trials on an inkjet press have matched the printing characteristics of offset litho for the first time.
The company created a challenging test form and ran it on the Screen TruepressJet 520HD using SC inks on a standard coated paper and concluded that the “output of the Screen TruepressJet 520 HS SC inkjet web press is suitable for commercial colour work that requires offset sheetfed quality”.
The test involved running more than 5,000 metres of paper through the press without coating before or after printing. The paper chosen was Verso Sterling Ultra Gloss. The aim was to replicate offset printing in both quality of reproduction, ink adhesion, dry back and consistency through the run. This needed to be maintained by the digital front end from start to finish.
Image Test Labs will normal run assessments on digital presses to measure the acceptability of image quality from all types of digital press. This resulted in a suite of applications for digital print quality called ImageGrader, recognised by the GATF winning one of InterTech Technology Awards in 2017. It is used to match output across different presses and to ensure that individual machines remain consistent.
ITL founding partner Henry Freedman says in a report in Printing Impressions magazine: “We noticed the offset match possibility when we measured the press output as part of the normal testing services we provide to commercial printing firms.
“We have shied away from trying such a match until now. The fact that we can image directly to conventional offset web paper, with no precoating, and run the same paper on both the offset and inkjet web presses, combined with the very high colour image quality of the TruepressJet 520 HD SC, made us confident that the Screen press could stand on an even footing with offset printers. The SC ink resistance to abrasion and rub-off was so great that our independent testing facility did not believe that the samples they tested were inkjet.”
The testing was carried out at the Screen Americas demonstration facility with the offset sheets and digital test forms produced by Cohber in Rochester, New York.
Screen was declaring its TruepressJet 520 HD running SC inks as 'beyond offset" during the Hunkeler Innovations Days this year, a sentiment that has been endorsed by sophisticated trials in the US.