August 29, 2016 By Jon Robinson
For three decades, Martin Bailey has developed unique expertise in building products for processing digital documents. He was a principle driver behind the JDF and JMF formats as CEO of CIP4 from its inception in 2000 until late 2006. He has lead a range of CGATS, ISO and PDF/X task forces as a global expert on industry standards and page-description languages.
As CTO of Global Graphics for the past decade, his knowledge is infused into the ubiquitous Harlequin RIP. PrintAction spoke with Bailey about the company’s new Fundamentals program to help inkjet press manufacturers overcome technical hurdles.
What is Global Graphics Fundamentals?
MB: For the last several years, a number of inkjet vendors have approached us with questions on whether we can help them build DFEs to go with inkjet presses that they have created or solve problems around the speed or quality on presses they are already shipping. And now Eric Worrall is heading up our [BreakThrough Engineering Service] and we’ve essentially formalized what we had been doing in a more ad-hoc manner. [Fundamentals] is designed to allow a press vendor to bring a new press to market more quickly and to be more confident that it is actually going to deliver the speed and quality and functionality that they want to provide to their users.
What area is of most concern for inkjet?
MB: We have talked quite a lot over the last couple of years, in particular, about halftone ink quality of using greyscale heads on single-pass inkjets. It is an area that a lot of people seem to be struggling with.
Why is there little inkjet screen discussion?
MB: There [is] very good technology in the wide-format space – multi-pass, fairly slow speeds, with many inks and levels of droplet size on the heads… but we do not see people doing significant work on the half-toning in the high-speed, single-pass production space. We do find that there are real problems there. That the drop placement isn’t as accurate as you would really like it to be, partly because of dot shape deformations, because you get elliptical marks where the drop actually hits because the substrate is moving so rapidly.
You tend to have pseudo random coalescing of adjacent dots. It is quite not random enough though. There tends to be a directionality to it, so that at normal reading distance you get a visible texturing. We have been working with three or four press vendors for a couple of years now to improve the output they can produce on their presses – to absolutely minimize the texturing effects and simultaneously ensure we are hitting the maximum total area coverage, ink lay down.
What is the best screening approach?
MB: There are good reasons to do the screening in different places depending on the workflow. In many cases, it makes sense to do the screening inside the RIP, if you can, simply because you are moving less data around post-RIP… When you consider that the fastest inkjet presses at the moment consume something around 20 gigabytes of raster per second then reducing that data transport requirement is a very significant gain.
But, in other cases, there are good reasons why people want to do the screening at the last minute in order to do on-the-fly recalibration, or head-to-head calibration, because of the width of the press, etcetera, and do that in a near close-loop environment… There are people who are using other people’s RIPs and unhappy with the quality they get from the screening or the speed they get at the screening. It is a very useful first step for them to say, ‘I am going to throw away the screener that came with the DFE… I am going to plug in Global Graphics ScreenPro because it is a lot faster and gives the quality I need.’
How are inkjet speeds and DFEs related?
MB: Building a DFE for one of these very, very high speed [inkjet presses] requires as much emphasis on systems engineering as it does on the RIPping, colour management, etcetera… that is hitting 1,000-feet-per-minute speed, which is aqueous. A lot of the people we tend to be working with at the moment are on UV and it is coming out at about 230/250 feet per minute. So far it is a lot slower than aqueous. I do not know if it is going to stay that way.
When will inkjet move deeper into commercial print sectors?
MB: They are pecking away at a number of different sectors to start with… Obviously, the direct-mail market as a sort of adjunct to the transactional space, where inkjet has been used for decades, but now pushing into much more graphically rich work.
They are being used in the book and publication space. It is also being used in some of the newsprint markets, which is kind of relating to book. It hasn’t really gone into magazines yet, because it is only fairly recently that aqueous inkjet presses have got to the point where you can print at a sensible price on coated paper. That has been a fairly big breakthrough in the last year, 18 months.
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