In this latest post, Global Graphics CTO Martin Bailey goes back to basics and explores what you need in a RIP to drive a digital press for labels & packaging.
Martin highlights rendering your jobs correctly, color management with CMYK inks and spot colors, PDF layering and technical separations, and provides a high-level view of the features of the Harlequin RIP® for digital labels and packaging.
Our corporate communications director, Jill Taylor, talks to Roy Faigenbloom of HP Indigo at Labelexpo Europe last month about the new digital front end driving the HP Production Pro for Indigo labels & packaging.
HP Indigo chose the Harlequin RIP as the RIP engine in this new DFE, which has been designed to drive all HP Indigo digital labels and packaging presses and has been rated as 5x faster than the previous DFE.
Just when you’ve all cozied down with PDF 1.7 what happens? Yes, that’s right. A new standard rears its head.
Around the middle of 2017 the ISO committee will publish PDF 2.0 (ISO 32000-2). So by the end of 2017 you’ll probably need to be considering how to ensure that your workflow can handle PDF 2.0 files correctly.
As the primary UK expert to this committee I thought I’d give you a heads up now on what to expect. And over the coming months via this blog and our newsletter I’ll endeavor to keep you posted on what to look out for as far as print is concerned. Because, of course, there are many aspects to the standard that do not concern print at all. For instance there are lots of changes in areas such as structure tagging for accessibility and digital signatures that might be important for business and consumer applications.
As you probably already know, in 2008 Adobe handed over ownership and development of the PDF standard to the International Standards Organization. Since that time I’ve been working alongside other experts to ensure that standards have real-world applicability.
And here’s one example relating to color.
The printing condition for which a job was created can be encapsulated in professional print production jobs by specifying an “output intent” in the PDF file. The output intent structure was invented for the PDF/X standards, at first in support of pre-flight, and later to enable color management at the print site to match that used in proofing at the design stage.
But the PDF/X standards only allow a single output intent to be specified for all pages in a job.
PDF 2.0 allows separate output intents to be included for every page individually. The goal is to support jobs where different media are used for various pages, e.g. for the first sheet for each recipient of a transactional print job, or for the cover of a saddle-stitched book. The output intents in PDF 2.0 are an extension of those described in PDF/X, and the support for multiple output intents will probably be adopted back into PDF/X-6 and into the next PDF/VT standard.
But of course, like many improvements, this one does demand a little bit of care. A PDF 1.7 or existing PDF/X reader will ignore the new page level output intents and could therefore produce the wrong colors for a job that contains them.
In my next post I’ll be covering changes around live transparency in PDF 2.0. Bet you can’t wait!
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The last few years have been pretty stable for PDF; PDF 1.7 was published in 2006, and the first ISO PDF standard (ISO 32000-1), published in 2010, was very similar to PDF 1.7. In the same way, PDF/X 4 and PDF/X 5, the most recent PDF/X standards, were both published in 2010, six years ago.
In the middle of 2017 ISO 32000-2 will be published, defining PDF 2.0. Much of the new work in this version is related to tagging for content re-use and accessibility, but there are also several areas that affect print production. Among them are some changes to the rendering of PDF transparency, ways to include additional data about spot colors and about how color management should be applied.
Meet Srikrishna Nudurumati, Global Graphics Colour Scientist and a member of our Fundamentals BreakThrough Engineering Services team. Srikrishna is passionate about colour and has many years of experience working in the field. We asked Srikrishna a few questions so you can get to know him better:
In his own words …
Tell us about your job. What do you do? Broadly, I am a physicist with specific interest in applications of colour vision & imaging research to software products. In my current role at Global Graphics, as a Colour Scientist, I lead the research & development to ensure best quality reproduction with our products as well as for our customers through our software and engineering services package, Fundamentals.
What is the best thing about your job? An exceptional aspect about my job in colour imaging is that colour is also my hobby. What more? Time is the only limit. We at Global Graphics, strive continuously, helping our customers to be the first to embrace the latest advancements in the industry. I am glad to be at the forefront, influencing to provide the best to our customers.
Tell us about the path you took to get where you are today My academic background stems from remote sensing, satellite imaging, digital photogrammetry and colour image processing. I have gained considerable practical knowledge of computer vision, pattern recognition and machine learning on the job during my initial assignments as a junior researcher. My IT career path from a software programmer working in medical imaging, to a researcher in colour engineering software was not planned. I strongly believe in Kaizen, even for improving one’s knowledge. During the past twelve years, I have made it a mandatory part of my daily schedule to learn something new and I continue this tradition today.
What is the biggest lesson you’ve learned in your career so far? I have been a part of the IT industry, as a software design engineer and also briefly in academia as a PhD researcher. I am happy to have learnt numerous invaluable lessons in my career so far already. It is imperative to align one’s interests with the general mission and goals of the organisation one works for. Identifying and being a part of an organisation, which facilitates such an alignment defines the first step to success. I work with an entrepreneurial instinct when it comes to defining, scoping and accomplishing my responsibilities, but with alignment to the organisation’s goals. That said, everyone in an organisation must be an influencer to whatever extent he/she can be.
As a colour expert, what’s the most important aspect of colour in your opinion? It is an important consideration that we are all different in the way we think of colour and perceive colour. Although colour and vision science establishes these variances to a very large extent, conventional colour engineering has not adopted these quite well. Colour engineering for printing is not based on a single branch of physics, but is a conglomerate of various phenomena, the roots of which lie in different realms of physics. The challenge that a colour scientist tries to address is to make it clear to the end user in an intuitive manner, how each parameter influences the overall quality of reproduction, be it for the display screen for softproofing or a print.
What are the challenges in successful colour engineering for printing? Colour management workflow for reproduction by printing is much more complex than for colour reproduction on display systems & screens. The physical model of a printing system comprises a colour workflow similar to that of a camera or a display system, but additionally deals with ink-media physical and optical interaction, grey balance, multilevel colourants, screening or halftoning, effects of metamerism and user preferences etc, in the form of inverse models. Added to these are the uncertainties in the reproduction chain. This could be uncertainty in the actual printer gamut, uncertainty in the printer mechanical behaviour in the field, differences in viewing environment etc. It is a challenge to provide the end users a system which makes them oblivious to the intricacies of the underlying mathematical models that transform the colour seamlessly from image capture to printed reproduction. We at Global Graphics provide our customers with a simplified view and controls for colour management, to tune their systems. This lets them focus their efforts in bringing out their creativity without worrying about numerous parameters that they would otherwise have to balance manually.
Fundamentals offers inkjet press manufacturers a quicker way to get their presses to market. It is a new concept that combines the software products that are essential to create your Digital Front End with our BreakThrough Engineering Service that helps you overcome the technical hurdles involved in developing a new press. Visit http://www.globalgraphics.com/products/fundamentals for more information.
You often read news items about a new press having been installed at a beta site but it’s not a topic that gets much of an airing apart from the odd news bulletin, is it?
And that got me thinking.
What is considered to be a successful beta test? And why should we care?
Well, if you do care, you are not just going through the motions to get your press out of the door. You are more likely to be focussed on delivering a good product. You probably view beta testing as an opportunity to make changes for the better and to help improve product management. You care what comes back because you want to develop a good product. It’s important to you to get understandable and useful data.
So what do you want to know? Your beta test should provide you with proof points as to why your printer is going to be successful in the market. “Real” users will use and abuse your press and put it through its paces in a way that your own internal hardware and software engineers will not. Any weaknesses will be exposed. And you’ll get closer to your customer by working together with them in a way that just wouldn’t be open to you if you didn’t run a beta program.
The thing is how do you extract meaningful data from your test? And how do you rule out those problems that have nothing to do with your press, such as humidity, ambient temperature, the way the site is being operated?
Somehow you need to control the environment that the beta test is conducted in and approach the beta test in quite a formal way to rule out any subjectivity that might creep in.
We’ve got some ideas on how to achieve this which I’ll share in another post. But I’d be interested in hearing how you do it. What are your top tips?
It’s been a really interesting week chatting to vendors and the press about our new software and services package for inkjet. In case you missed it, we’ve called it Fundamentals because it combines essential software components and engineering expertise that press vendors need to build a Digital Front End.
What’s the big deal you might say? Well, The Times They Are A Changing to quote Bob Dylan both in terms of the progression of inkjet technology and the swing towards digital printing in the labels and packaging sector which is where we have focussed our initial offering of Fundamentals.
Thanks to our lengthy graphic arts experience – we’ve been supplying software to drive digital presses since 2002 – we are regularly approached by inkjet press vendors either to intervene at some point in an existing workflow or because they’re starting from a blank sheet of paper and need to figure out how to build a Digital Front End for a new press.
If they have an existing DFE a press vendor might be stuck on output quality, or maybe they can’t get the throughput in speed that they need. If they’re building a new press they might not know where to quickly source the components they need. Or often they can’t allocate enough engineering resource to the DFE when they need to. Plus it takes a very special skill set to know how to wire it all together.
How do we know all this? Because vendors tell us so. And Fundamentals is our response to this market demand. It offers best of breed software products with an engineering service that allows the press vendor to address their specific applications.
It will grow, of course. We are already looking at a Fundamentals software bundle for industrial inkjet for example. But the good news for press vendors is that we can do all of the above and then some!
One of the many highlights of our drupa stand will be the new Harlequin RIP. We asked Martin Bailey, CTO at Global Graphics, to tell us more about it. He told us that there are a host of new features to improve inkjet output quality including richer, multi-level screening controls, more controls for variable data printing, and new features for labels and packaging applications. Hear his summary in this video below.
Fancy a test drive? Join us at drupa 2016, Stand 70 B21/C20 in the dip. Simply contact us to book a demonstration.
Stay tuned for more announcements over the next couple of weeks.
Remember in olden times how you sent a file to print on a wing and a prayer? OK, it wasn’t that bad! But it was unreliable. Figures showed that print-ready file delivery had failure rates of between 30 – 70% and this was a real problem for print service providers with high throughput like magazine houses.
Then PDF/X came along and greatly improved the situation. It was strengthened by additional standardisation efforts from several other bodies including Ghent PDF Workgroup and Altona.
PDF/X worked because it ensured delivery of files ready to high-quality print. And because it dealt with the headache so well, print service providers recommended it.
Fast forward for a moment to today and to the tidal wave that is variable data printing. Most buyers deliver the brief and the dataset to the print service provider (PSP). A full service PSP will offer data mining, graphic design, composition and print. Offering a full service promises higher margins. If you only provide a print service you can expect lower margins, but your model connects better to web-to-print services that are burgeoning. But if you try to “just print” VDP jobs, those that fail will eliminate profit.
I’ve been invited to speak at the Online Print Symposium in Munich (17th – 18th March) about why PDF/VT and Industry 4.0 are set to change online print forever. The truth is that VDP has been hanging around street corners looking for a PDF/X. Well, now it’s found one because that’s what PDF/VT is. It’s been created to deal with every page being different and to give PSPs more control over the workflow.
I would go so far to suggest that print-ready file delivery of graphically rich variable data from outside the print company is unlikely to succeed without it! And on that bombshell…!
Standards for variable data printing (VDP) have come a long way since the first work by CGATS to develop a universal delivery format in the late 1990s. In 2010 the International Standards Organization published the PDF/VT standard, marking the first really effective specification for a reliable, vendor-neutral exchange of variable data jobs, both within and between companies.
A special type of the PDF file format, PDF/VT is specifically used for variable data and transactional printing in a variety of environments, from desktop printing to high volume digital production presses. Built on PDF/X, it therefore brings all the advantages of that standard in enforcing best practices for reproducible and predictable color and appearance to the variable data and transactional print worlds.
The industry is gradually realizing its value to improve quality, competitiveness and productivity, and I’ve been working with the PDF/VT Competence Center, especially with Christoph Oeters (Sofha), Paul Jones (Teclyn bv) and Tim Donahue (technical consultant) to produce a new set of Application Notes highlighting the benefits of using PDF/VT and the workflows that it enables.
The Application Notes explain how to make the highest quality and most efficient PDF/VT files to achieve the required visual appearance of a job, so if you develop software to read and write PDF/VT files, for example in composition tools, RIPs, digital front ends and imposition tools, or if you work on print workflow integration, you’ll find the notes really beneficial. They also show how document part metadata can be applied and leveraged for VDP specific production workflows.
Of course, there are wider benefits to using PDF/VT: The adoption of PDF/VT will allow the industry to finally move towards a reliable, vendor-neutral exchange of variable data jobs, simplifying the process of variable data printing significantly.
There’s been a lot of emphasis in the industry recently on perceived resolution. I’m sure you will have come across the phrase from major vendors:
“The Xerox Rialto 900 (…) offers 1,000 dpi perceived resolution for high quality output.”
Oce Vaior Print i300: “The multilevel dot modulation in combination with 600x600dpi resolution boosts the print quality of image elements and shadings to perceived 1200 dpi.”
But what is resolution anyway, and is it the only thing we need to worry about to ensure high quality output?
How we perceive resolution has changed over the years. For conventional print and first generation digital presses (except for wide format), resolution was two dimensional (across and along the media). More recently, inkjet presses (and some toner) can place different amounts of colorant at each location on the substrate, using greyscale heads, multiple passes with the same head, or multiple heads imaging at the same location. This means that resolution has effectively become 3D: not only along and across the media, but also in the amount of colorant applied at any single pixel position.
At Global Graphics we call this “multi-level output”, compared to the “binary” output where each pixel can either be coloured or not, with no intermediate steps.
Resolution? Or addressability and droplet size? As print geeks know well, press resolution has very little to do with resolving power, it is really a marketing simplification to use the word ‘resolution’ for ‘addressability’ – e.g. at 600 dpi, each addressable pixel is 1/600” from its neighbours. The detail that can be displayed is a factor of droplet size as well as addressability; as droplets get bigger each one covers more than just a single (square!) pixel on the media, so less fine detail is retained.
Droplet placement accuracy also comes into play. In a perfect world we would have a regular grid of droplets, but in practice we don’t usually get one. The variation in separation between droplets can lead to coalescing, mottling or streaking on some substrates, especially on UV inkjet presses, but it can occur on aqueous as well.
Addressability and droplet size affect the rendering of small type and other high-contrast fine detail. Droplet placement accuracy affects texture of final print. So we still don’t have a clear metric for “perceived resolution” …
What about resolution and bit depth? Using multi-level output can produce smoother rendering of images and other graphics with gradual tone or colour changes than binary output at the same resolution can achieve.
But nozzle redundancy is also vital: In a single pass press, with a page-wide array, a single blocked nozzle will leave a white line down the substrate unless something is built in to fix that, such as nozzle redundancy. And that redundancy must use up some of the press’ capability to use multiple nozzles in the same location for multi-level output, so 1200 dpi nozzles often doesn’t mean 1200 dpi addressability on the substrate.
And sometimes each nozzle can only deliver one droplet size; sometimes it can deliver a variety of sizes.
So what’s the real quality that these presses are capable of? We need a lot of information to really understand what’s going on: dpi across and along the media, number of nozzles imaging any single pixel, droplet sizes available from that nozzle, proportion of nozzles used for redundancy … I don’t think I’ve ever seen a press vendor’s public specification that gives us all the information we want.
Can we even say, simplistically, that higher resolution and bit depth are good? If everything else is equal then yes, in many cases, except that you can push either too far. On an aqueous inkjet, higher resolutions really need smaller highlight droplets; smaller lone droplets tend to disappear into some media and can lead to loss of extreme highlights on the output. Interestingly you end up with output that looks remarkably close to the way flexo loses those same highlights!
And you also need to remember that higher addressability means high computational requirements, and more computations mean more expensive DFEs, higher running costs, maybe even less green … (a faster RIP can offset this, of course!) It also makes the press more expensive, and harder to run as fast.
And what’s the impact on quality? There are other factors other than bit depth, addressability and droplet size and placement which affect the final result, for example:
Items affecting ink spread or movement on the substrate such as paper smoothness, absorbency, coatings, ink viscosity and surface tension;
Movement of the colorant into the substrate, reducing the capability of showing very small detail or saturated colours.
Colour management, including ink limitation and reduction
So the ‘virtual’, mathematical discussion of resolution and droplet size are is certainly not the only factor in determining the quality of output. Quality arises from a complex mix of heads, electronics, wave forms, inks, media, resolution, registration, bit depth and half-toning etc. We don’t have a good way to provide a single, understandable quality metric to sum it all up. ISO DTS 15311-1 is defining testing and reporting methodologies in this area, although it still doesn’t provide a simple quality metric.
So what’s the answer? We just don’t have a single number that sums up the quality capability of a digital press at the moment. But then simply reporting ‘resolution’ has never really fulfilled that role in the past for binary systems, from imagesetters to platesetters to office printers … to digital cameras. So perhaps we shouldn’t be too disappointed.
What should you do when a vendor reports “perceived resolution”? I’d suggest that you take it as an indication of the level in the marketplace that the vendor is intending to address … and then draw your own conclusions based on print samples.
If you’re looking to buy a press, have the vendor:
Print samples on the media and at the speed that you expect to use
Use a variety of graphical constructs to explore press behaviour:
Flat tints at a range of tones and colours
Smooth graduations, including some long ones all the way to white
Photographic images, including high and low key, soft-focus and sharp detail
Fine vector detail such as small serif and sans serif text
If you’re already running a press do the same. Each technology has different strengths and weaknesses; you may even need multiple presses to address all work in your particular target sector. The key thing is to understand what your presses are good at, and what to avoid, and then to work with your customers to achieve the best possible result … and to set expectations appropriately in advance.
If you’re a press vendor, talk to us about how Global Graphics’ multi-level screening technologies can maximise the quality and the value of your hardware.
Readabout our latest advances in screening, presented at the Inkjet Conference, October 2015.