Is your printer software up to the job? The impact of rising data rates on software evolved from traditional print processes

Direct™ product manager Ian Bolton explores the impact of using software that has evolved from traditional print processes to drive digital inkjet presses as they advance to print faster, in higher resolution, a wider variety of colors and applications. In particular, Ian focuses on the impact that rising data rates have on the workflow:

Digital press software evolved from traditional print processes has already reached its limit. Digital presses are becoming higher resolution – most are moving from 600 dpi to 1200 dpi, quadrupling the data. They’re also becoming deeper, with up to 7 drop sizes – and these drops are being made from a wider variety of colors. Digital presses are also becoming wider, up to 4 meters wide, and faster,  up to 1,000 feet per minute!

And what if you need to print where every item is different? For example, fully personalized – like curtains, flooring, wall coverings, clothing etc. All of these require software that can deliver ultra-high data rates.

Let’s look at how those data rates scale up as digital presses advance:

The next generation presses demand ultra-high data rates
The next generation presses demand ultra-high data rates

If we start with 600 dpi, 20 inches wide, 3 drop sizes and 100 m per minute, then that’s 120 MBps per colorant, which is not too challenging. But once we move up to 1200 dpi, we’ve now quadrupled the data to 480 MBps, which is the read speed of all but the most bleeding-edge solid state drives today.

With printhead, nozzle and roller technology improving, the rated speeds also increase, so what happens when we go up to 300 m per min? It’s now 1.4 GBps and you will need one of those bleeding-edge solid state drives to keep up, bearing in mind you will now be writing as well as reading.

And if we go wider to print our wallcoverings at 40 inches wide, we’re now at 2.8 GBps … and we want our walls to look great close up, so we might be using 7 drop sizes, which takes us up to 5.7 GBps … and this is all just for one colorant!

Based on these numbers, it should be clear now that, for this generation of digital presses and beyond, a disk-based workflow just isn’t going to cut it: reading and writing this amount of data to disk would not actually be fast enough and would require ridiculous amounts of physical storage. This is where software evolved from traditional workflows hits a barrier: the data rate barrier.

To solve this we need to go back to the drawing board. It’s similar to the engineering challenge of moving from propeller-driven aircraft to jets that could break the sound barrier. Firstly, you need to develop a new engine and then you need to commercialize it.

So, if you’re looking for software to power your first or next digital press it’s going to need the right  kind of software engine that isn’t based on disk technology so that you can drive your digital press electronics directly and smash through the data rate barrier. In other words, you need to go Direct.

To learn more about the impact of rising data rates and how you can futureproof your next digital press, visit our website to find out more about going Direct.

Further reading:

Future-proofing your digital press to cope with rising data rates

If you’re interested in calculating data rates take a look at this blog post where you can download your own data rate calculator: Choosing the class of your raster image processor

About the author

Ian Bolton, Product Manager, Direct
Ian Bolton, Product Manager – Direct
Ian has over 15 years’ experience in industry as a software engineer focusing on high performance. With a passion for problem-solving, Ian’s role as product manager for the Direct™ range gives him the opportunity to work with printer OEMs and break down any new technology barriers that may be preventing them from reaching their digital printer’s full potential.
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Second edition now available: Full Speed Ahead: How to make variable data PDF files that won’t slow your digital press

At the beginning of 2020, in what we thought was the run-up to drupa, Global Graphics published a new guide called “Full Speed Ahead: How to make variable data PDF files that won’t slow your digital press”. It was designed to complement the recommendations available for how to maximize sales from direct mail campaigns, with technical recommendations as to how you can make sure that you don’t make a PDF file for a variable data job that will bring a digital press to its knees. It also carried those lessons into additional print sectors that are rapidly adopting variable data, such as labels, packaging, product decoration and industrial print, with hints around using variable data in unusual ways for premium jobs at premium margins.

Well, as they say, a lot has happened since then.

And some of that has been positive. At the end of 2020 several new International Standards were published, including a “dated revision” (a 2nd edition) of the PDF 2.0 standard, a new standard for submission of PDF files for production printing: PDF/X-6, and a new standard for submission of variable data PDF files for printing: PDF/VT-3.

We’ve therefore updated Full Speed Ahead to cover the new standards. And at the same time we’ve taken the opportunity to extend and clarify some of the rest of the text in response to feedback on the first edition.

So now you can keep up to date, just by downloading the new edition!

DOWNLOAD THE GUIDE

Further reading:

  1. What’s the best effective photographic image resolution for your variable data print jobs?
  2. Why does optimization of VDP jobs matter?

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MPI Tech joins the Global Graphics Software Partner Network

MPI Tech joins the Global Graphics Software Partner Network

Leading provider of document management and document output solutions MPI Tech has joined the Global Graphics Software Partner Network as a technology partner.

MPI Tech will enable Global Graphics Software’s Harlequin Direct™ and Fundamentals™ products to support AFP and IPDS  jobs. AFP (Advanced Function Presentation) is the most widely used format for high-speed transactional printing in many industries including finance, insurance, manufacturing, health care and education. IPDS (Intelligent Printer Data Stream) is the print description language (PDL) to print AFP documents online.

MPI Tech offers a range of solutions to process AFPDS and native AFP/IPDS at speeds over 6,000 ipm or convert them into the most popular PDL (PCL, PDF, PDF/A, PS etc) on almost every platform (Windows, AIX, Linux, Solaris, UNIX).

Justin Bailey, managing director of Global Graphics Software commented: “We’re pleased to welcome MPI Tech to our partner network. With a proven technology and know-how for processing AFP or IPDS print jobs, Global Graphics Software turns to MPI Tech as its ‘go-to partner’ when our customers require solutions for these transactional print data-streams.”

MPI Tech has been a licensee of Global Graphics technology for many years, using it for converting to, and processing, PostScript, PDF, and other PDLs.

If you’re interested in joining the Partner Network visit our website to find out more.

 

Image Access joins the Global Graphics Software Partner Network

Image Access offers book, flatbed, sheetfeed, duplex & art scanners for digitizing large format originals for archives, libraries, museums & industry.
Image Access offers book, flatbed, sheetfeed, duplex & art scanners for digitizing large format originals for archives, libraries, museums & industry.

Leading German scanner manufacturer Image Access GmbH has joined the Global Graphics Software Partner Network as a technology partner. The two companies began working together last year to develop a solution that would enable printer vendors to implement a new family of Image Access line scan bars called WideSCAN into their printers to support the creation of PrintFlat™ calibrations. The WideSCAN scan bars, together with PrintFlat, will dramatically increase print quality with minimal impact on overall production time.

PrintFlat technology maximizes the print quality of your printer by addressing common defects found in inkjet printing, including banding and stripes, as well as mottling, streaking and chaining. By adding PrintFlat to a print workflow it helps to boost printer sales and reduce support calls for OEMs by expanding the range of printable jobs and consistently achieving exceptional image quality.

For the PrintFlat process to work, printed target pages need to be scanned and the resultant image data fed into the PrintFlat solution. This is where the Image Access partnership comes into play: the WideSCAN scan bars will be available in various sizes in 12-inch increments, starting at 24 inches, and are the most compact and easy-to-use line scan bars in the industry.

Justin Bailey, managing director of Global Graphics Software commented: “Image Access are known for their experience and innovative use of emerging camera technologies and I’m really pleased to welcome them to our Partner Network. Introducing the new WideSCAN scan bar is a game changer for printer manufacturers. Now they will be able to implement the scan bar into the printer so that calibration and PrintFlat correction can all be done inline on the printer, making that device PrintFlat Ready.”

Image Access has manufactured wide format scanners, including brands Bookeye® and WideTEK®, for more than 25 years.

If you’re interested in joining the Partner Network visit our website to find out more.

 

A passion for software development

If you’re a recent mathematics or computer science graduate, or have a year or two of real software development experience, then we want to hear from you.

 Henry Sanderson, Software Engineer at Global Graphics Software

Meet Henry Sanderson, software engineer at Global Graphics Software. Henry joined us in 2019 on our graduate scheme.

What is your background?

My programming journey started at A-level where I first took an interest in the subject, never having had a formal opportunity to study it before. I followed the path all the way through to graduating with a first-class degree in Computer Games from the University of Essex.

What was the graduate  scheme selection day like?

The day was built around a specific task, which was both fun and challenging. There were some surprises, but they were integral to the experience so they could see how we’d react, which was interesting to say the least. For example, we were working in groups, but we weren’t given much in the way of source control, to see how we’d cope merging our work together at the end. It was a cool way to introduce some chaos.

Tell us a bit about your Global Graphics Graduate Program experience

The scheme is separated into three sections where each is spent in a different discipline of QA, Support, and Development, each lasting about four months. There’s also an initial period where you’re taught the basics and get to integrate with the company for a bit. You learn quite a few tricks that’ll be useful too, one of which being how to use ReSharper to speed up your overall pace of working. I initially thought I’d only be interested in development, but I was enlightened to the other two disciplines in a way that I enjoyed. I was involved in meaningful projects the whole way, so there’s no feeling of apathy since everything you do is useful to the company.

For QA, we were tasked to investigate a new way of implementing UI testing that would be competitive to the current choice, and the result of that was a successful integration of a new UI testing library that was significantly cheaper and didn’t require juggling licenses between PCs.

What has been your experience since graduating the program?

I graduated the program feeling pretty good about my progress made during my time here. I entered this company with very little C++ knowledge and below-average C# knowledge, and on graduation I felt that I was a lot more competent at both, as well as skills beyond just knowing languages: using source control, exploring the parts of IDEs that I took for granted while studying at university and using programs that I’d never even heard of before joining. I’ve definitely grown as a person too. I’m now a developer on the Direct™ product team, which has been a rigorous trial by fire by diving head-first into a C++ codebase. I am certainly happy with where I am in the company now and want to continue to develop myself as a member of the team.

How would you describe the support you received from your mentorship team?

The support I received was instrumental in my development here. It was hugely effective, with just the right amount of assistance given so that it neither felt like handholding nor isolating.

What’s the best thing about working at Global Graphics Software?

The flexibility is amazing. The workday isn’t a fixed block of time, it’s whatever you want it to be (within reason). The ethos is basically “as long as the work gets done, and you turn up to meetings, work however long you want”, which is a boon to someone like me who has trouble getting out of bed promptly.

What is the environment like?

The office in Cambourne has a roomy atmosphere with lots of natural light, with a well-stocked kitchen to handle our metabolic needs. There’s also a huge expanse of green space outside the office too, which is perfect for going for mind-clearing walks.

What is the most exciting thing about your work?

I’m in it for the knowledge gained, since in under two years I feel like my skills have increased greatly. Every task I pick up offers the chance to enrich my understanding somewhere.

How have you found working remotely?

Before the pandemic, I very rarely worked from home, but now having done it consecutively every day since early March, I’m very much used to it and don’t think I could return to normal. The company has really embraced working from home and have implemented the systems required to make it work well, to the point that I don’t really feel disadvantaged from the situation imposed on me.

Have you taken part in any of the social events?

I’m a fan of the board game nights that were picking up steam shortly before lockdown, as well as the Shed meetups.

What advice would you give this year’s graduates?

As long as you have the enthusiasm to learn and grow, and can go with the flow, there’s nothing to really worry about. ‘Don’t suffer in silence’ is the mantra to grow here. Ask questions when you get stuck or if you need something explained.

If you’re interested in joining the Global Graphics Software Graduate Program visit our web page to find out more:
https://www.globalgraphics.com/company/careers/graduate-program

Improving PDF accessibility with Structure Tagging

In this week’s post, Global Graphics Software’s principal engineer, Andrew Cardy, explores the structure tagging API in the Mako™ Core SDK. This feature is particularly valuable as it allows developers to create PDFs that can be read by screen readers, such as Jaws®. This helps blind or partially sighted users unlock the content of a PDF.  Here, Andy explains how to use the structure tagging API in Mako to tag both text and images:

What can we Structure Tag?

Before I begin, let’s talk about PDF: PDF is a fixed-format document. This means you can create it once, and it should (aside from font embedding or rendering issues) look identical across machines. This is obviously a great thing for ensuring your document looks great on your user’s devices, but the downside is that some PDF generators can create fixed content that is ordered in a way that is hard for screen readers to understand.

Luckily Mako also has an API for page layout analysis. This API will analyze the structure of the PDF, and using various heuristics and techniques, will group the text on the page together in horizontal runs and vertical columns. It’ll then assign a page reading order.

The structure tagging API makes it easy to take the layout analysis of the page and use it to tag and structure the text. So, while we’re tagging the images, we’ll tag the text too!

Mako’s Structure Tagging API

Mako’s structure tagging API is simple to use. Our architect has done a great job of taking the complicated PDF specification and distilling it down to a number of useful APIs.

Let’s take a look at how we use them to structure a document from start to finish:

Setting the Structure Root

Setting the root structure is straight forward. Firstly, we create an instance of IStructure and set it in the document.

Next we create an instance of a Document level IStructureElement and add that to the structure element we’ve just created.

One thing that I learnt the hard way, is that Acrobat will not allow child structures to be read by a screen reader if their parent has alternative (alt) text set.

Add alternate text only to tags that don’t have child tags. Adding alternate text to a parent tag prevents a screen reader from reading any of that tag’s child tags. (Adobe Acrobat help)

Originally, when I started this research project, I had alt text set at the document level, which caused all sorts of confusion when my text and image alt text wasn’t read!

Using the Layout Analysis API

Now that we’ve structured the document, it’s time to structure the text. Firstly, we want to understand the layout of the page. To do this, we use IPageLayout. We give it a reference to the page we want to analyze, then perform the analysis on it.

Now the page has been analyzed, it’s easy to iterate through the columns and nodes in the page layout data.

Tagging the text

Once we’ve found our text runs, we can tag our text with a span IStructureElement. We append this new structure element to the parent paragraph created while we were iterating over the columns.

We also tag the original source Mako DOM node against the new span element.

Tagging the images

Once the text is structured, we can structure the images too.

Earlier, I used Microsoft’s Vision API to take the images in the document and give us a textual description of them. We can now take this textual description and add it to a figure IStructureElement.

Again, we make sure we tag the new figure structure element against the original source Mako DOM image.

Notifying Readers of the Structure Tags

The last thing we need to do is set some metadata in the document’s assembly, this is straight forward enough. Setting this metadata helps viewers to identify that this document is structure tagged.

Putting it all Together

So, after we’ve automated all of that, we now get a nice structure, which, on the whole, flows well and reads well.

We can see this structure in Acrobat DC:

And if we take a look at one of the images, we can see our figure structure now has some alternative text, generated by Microsoft’s Vision API. The alt text will be read by screen readers.

Figure properties dialogue
Figure properties dialogue

It’s not perfect, but then taking a look at how Adobe handles text selection quite nicely illustrates just how hard it is to get it right. In the image below, I’ve attempted to select the whole of the title text in Acrobat.

Layout analysis is hard to get right!

In comparison, our page layout analysis seems to have gotten these particular text runs spot on. But how does it fair with the Jaws screen reader? Let’s see it in action!

Struture tagging with Mako SDK

So, it does a pretty good job. The images have captions automatically generated, there is a sense of flow and most of the content reads in the correct order. Not bad.

Printing accessible PDFs

You may be aware that the Mako SDK comes with a sample virtual printer driver that can print to PDF. I want to take this one step further and add our accessibility structure tagging tool to the printer driver. This way, we could print from any application, and the output will be accessible PDF!

In the video below I’ve found an interesting blog post that I want to save and read offline. If I were partially sighted, it may be somewhat problematic as the PDF printer in Windows 10 doesn’t provide structure tagging, meaning that the PDF I create may not work so well with my combination of PDF reader and screen reader. However, if I throw in my Mako-based structure and image tagger, we’ll see if it can help!

Structure tagging video

Of course, your mileage will vary and the quality of the tagging will depend on the quality and complexity of the source document. The thing is, structural analysis is a hard problem, made harder sometimes by poorly behaving generators, but that’s another topic in itself. Until all PDF files are created perfectly, we’ll do the best we can!

Want to give it a go?

Please do get in touch if you’re interested in having a play with the technology, or just want to chat about it.

Andy Cardy, Principal Engineer at Global Graphics Software
Andy Cardy, Principal Engineer at Global Graphics Software

Andy Cardy is a Principal Engineer for Global Graphics Software and a Developer Advocate for the Mako SDK.

Find out more about Mako’s features in Andy’s coding demo:

SHARPEN THE SAW – A LIVE CODING DEMO USING MAKO™

Sharpen the Saw: Mako SDK demo

In this session Andy uses coding in C++ and C# to show you three complex tasks that you can easily achieve with Mako:
• PDF rendering – visualizing PDF for screen and print (15 mins)
• Using Mako in Cloud-ready frameworks (15 mins)
• Analyzing and editing with the Mako Document Object Model (15 mins)

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Shade and color variation in textile printing – why it’s important and what you can do about it

Printing soft furnishings

With fewer design limitations, a faster turnaround, no minimum run length and higher margins (not to mention reduced use of power and water, and of pollution), it’s not surprising that the digitally printed textile market is growing.1 Inkjet has certainly made textile design and printing much more flexible than screen printing – and that goes for everybody involved, from the designer through the printing company, to the buyer.

But printing textiles on inkjet doesn’t come without its challenges: as a software provider focusing on print quality issues, we often hear from print service providers who can only digitally print two thirds of the jobs they receive because they would not be paid for the quality they could achieve on the others.

Shade or color variation is a common problem. It’s not new in digital printing (it’s always been an issue for screen-printed and dyed textiles as well) and is usually managed by providing a shade band, which printer operators refer to, to check allowable color variations between pieces.

But, unlike screen-printing or dyeing, the color variation on an inkjet press can be visible over a small distance, just a few centimeters, and this results in visible bands across the output. Banding describes features that tend to be 1 – 10 cm across and they’re often caused by variation of inkjet pressure or voltage differences within the head, which typically results in a frown or smile shape. We also see a certain amount of manufacturing variation between heads so that one may print lighter or darker than the head next to it in a print bar. Some types of heads can also wear in use, which can result in less regular banding that can change over time. This means that large areas which should be flat color may not be.

When such a variation occurs it can greatly complicate a lot of post-print steps, especially if you need to put more than one piece of textile together, either in sewing or use (such as a pair of curtains). If that’s the case, then a significant difference may be unacceptable and your printing rejected by your buyer. Ultimately this leads to print service providers rejecting jobs, because they know their digital press can’t handle printing those tricky flat tints or smooth tones.

What can you do about it?

The first thing many companies do to try to overcome this banding is to adjust the voltage to the inkjet head, but this is often time-consuming and expensive because it requires an expert technician. A better alternative is to make the correction in software, which is a more cost-effective and faster solution. It means it can be automated and can act at a much finer granularity, so printing is more accurate. There’s no need to mess with controls that could damage the press, and printing companies themselves can make corrections without the vendor sending a technician on-site.

Our solution at Global Graphics Software for improving banding is PrintFlat™. It corrects tonality to hide banding based on measurements from the press. It adjusts every nozzle separately and doesn’t need a specialist engineer to make press adjustments. PrintFlat can be integrated into different digital front ends, using a variety of RIPs, including Caldera and Colorgate and, not to mention, our own Harlequin RIP®.

Over the years of working with many press manufacturers we’ve discovered that many technical issues and solutions are common across different sectors, including transactional, wide-format, commercial, labels and packaging, and industrial, including ceramics, wall coverings, flooring and of course textiles. That means that we already have years of experience in correcting for banding. Using PrintFlat in your press means print service providers can now take on those jobs they would normally reject.

To learn more about how to eliminate shade and color variation when printing on an inkjet press, listen to Global Graphics Software’s CTO Martin Bailey’s talk for FESPA 2020:

“New techniques to eliminate in-lot shade variation when printing textiles with inkjet.”

Or visit the PrintFlat website: https://www.printflat.com/

Further reading:

  1. What causes banding in inkjet? (And the smart software solution to fix it.)
  2. Streaks and Banding: Measuring macro uniformity in the context of optimization processes for inkjet printing

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  1. Digitally printed textiles are estimated to be between 2% – 5% of the total printed textiles market. Estimated at $146.5 billion in 2018 by Grand View Research

There really are two different kinds of variable data submission!

There are two completely different forms of variable data handling in  the Harlequin RIP®, and I’m sometimes asked why we’ve duplicated functionality like that. The simple answer is that it’s not duplication; they each address very different use cases.

But those use cases are not, as many people then expect, “white paper workflows” vs imprinting, i.e. whether the whole design including both re-used and single-use elements is printed together vs adding variable data on top of a pre-printed substrate. Both Harlequin VariData™ and the “Dynamic overlays” that we added in Harlequin version 12 can address both of those requirements.

Incidentally, I put “white paper workflows” in quotes because that’s what it’s called in the transactional and direct mail spaces … but very similar approaches are used for variable data printing in other sectors, which may not be printing on anything even vaguely resembling paper!

The two use cases revolve around who has the data, when they have it, whether a job should start printing before all the data is available, and whether there are any requirements to restrict access to the data.

When most people in the transactional, direct mail or graphic arts print sectors think about variable data it tends to be in the form of a fully resolved document representing all of the many variations of one of a collection of pages, combining one or more static ‘backgrounds’ with single-use variable data elements, and maybe some re-used elements from which one is selected for each recipient. In other words, each page in the PDF file is meant to be printed as-is, and will be suitable for a single copy. That whole, fully resolved file is then sent to the press. It may be sent from one division of the printing company to the press room, or even from some other company entirely. The same approach is used for some VDP jobs in labels, folding carton, corrugated, signage and some industrial sectors.

This is the model for which optimized PostScript, and then optimized PDF, PDF/VT (and AFP) were designed. It’s a robust workflow that allows for significant amounts of proofing and process control at multiple stages. And it also allows very rich graphical variability. It’s the workflow for which Harlequin VariData was designed, to maximize the throughput of variable data files through the Digital Front End (DFE) and onto the press.

But in some cases the variable data is not available when the job starts printing. Indeed, the print ‘job’ may run for months in situations such as packaging lines or ID card printing. That can be managed by simply sending a whole series of optimized PDF files, each one representing a few thousand or a couple of million instances of the job to be printed. But in some cases that’s simply not convenient or efficient enough.

In other workflows the data to be printed must be selected based on the item to be printed on, and that’s only known at the very last minute … or second … before the item is printed. A rather extreme example of this is in printing ID cards. In some workflows a chip or magnetic strip is programmed first. When the card is to be printed it’s obviously important that the printed information matches the data on the chip or magnetic strip, so the printing unit reads the data from one of those, uses that to select the data to be printed, and prints it … sometimes all in less than a second. In this case you could use a fully resolved optimized PDF file and select the appropriate page from it based on identifying the next product to be printed on; I know there are companies doing exactly that. But it gets cumbersome when the selection time is very short and the number of items to be printed is very large. And you also need to have all of the data available up-front, so a more dynamic solution is better.

Printing magnetic strip on ID cards
Printing magnetic strip on ID cards.

In other cases there is a need to ensure that the data to be printed is held completely securely, which usually leads to a demand that there is never a complete set of that data in a standard file format outside of the DFE for the printer itself. ID cards are an example of this use case as well.

Printing Example ID cards

Moving away from very quick or secure responses, we’ve been observing an interesting trend in the labels and packaging market as digital presses are used more widely. Printing the graphics of the design itself and adding the kind of data that’s historically been applied using coding and marking are converging. Information like serial numbers, batch numbers, competition QR Codes, even sell & use by dates are being printed at the same time as the main graphics. Add in the growing demands for traceability, for less of a need for warehousing and for more print on demand of a larger number of different versions, and there can be some real benefits in moving all of the print process quite close to the bottling/filling/labelling lines. But it doesn’t make sense to make a million page PDF file just so you can change the batch number every 42 cartons because that’s what fits on a pallet.

These use cases are why we added Dynamic overlays to Harlequin. Locations on the output where marks should be added are specified, along with the type of mark (text, barcodes and images are the most commonly used). For most marks a data source must be specified; by default we support reading from CSV files or automated counters, but an interface to a database can easily be added for specific integrations. And, of course, formatting information such as font, color, barcode symbology etc must be provided.

The ‘overlay’ in “Dynamic overlays” gives away one of the limitations of this approach, in that the variable data added using it must be on top of all the static data. But we normally recommend that you do that for fully resolved VDP submissions using something like optimized PDF anyway because it makes processing much more efficient; there aren’t that many situations where the desired visual appearance requires variable graphics behind static ones. It’s also much less of a constraint that you’d have with imprinting, where you can only knock objects like white text out of a colored fill in the static background if you are using a white ink!

For what it’s worth, Dynamic overlays also work well for imprinting or for cases where you need to print graphics of middling complexity at high quality but where there are no static graphics at all (existing coding & marking systems can handle simple graphics at low to medium quality very well). In other words, there’s no need to have a background to print the variable data as a foreground over.

So now you know why we’ve doubled up on variable data functionality!

Further reading:

  1. What’s the best effective photographic image resolution for your variable data print jobs?
  2. Why does optimization of VDP jobs matter?

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What is a Raster Image Processor (RIP)?

Ever wondered what a raster image processor or RIP does? And what does RIPping a file mean? Read on to learn more about the phases of a RIP, the engine at the heart of your Digital Front End (DFE).

The RIP converts text and image data from many file formats including PDF, TIFF™ or JPEG into a format that a printing device such as an inkjet printhead, toner marking engine or laser platesetter can understand. The process of RIPping a job requires several steps to be performed in order, regardless of the page description language (such as PDF) that it’s submitted in. Even image file formats such as TIFF, JPEG or PNG usually need to be RIPped, to convert them into the correct color space, at the right resolution and with the right halftone screening for the press.

Interpreting: The file to be RIPped is read and decoded into an internal database of graphical elements that must be placed on the output. Each may be an image, a character of text (including font, size, color etc), a fill or stroke etc. This database is referred to as a display list.

Compositing: The display list is pre-processed to apply any live transparency that may be in the job. This phase is only required for any graphics in formats that support live transparency, such as PDF; it’s not required for PostScript language jobs or for TIFF and JPEG images because those cannot include live transparency.

Rendering: The display list is processed to convert every graphical element into the appropriate pattern of pixels to form the output raster. The term ‘rendering’ is sometimes used specifically for this part of the overall processing, and sometimes to describe the whole of the RIPing process.

Output: The raster produced by the rendering process is sent to the marking engine in the output device, whether it’s exposing a plate, a drum for marking with toner, an inkjet head or any other technology.

Sometimes this step is completely decoupled from the RIP, perhaps because plate images are stored as TIFF files and then sent to a CTP platesetter later, or because a near-line or off-line RIP is used for a digital press. In other environments the output stage is tightly coupled with rendering, and the output raster is kept in memory instead of writing it to disk to increase speed.

RIPping often includes a number of additional processes; in the Harlequin RIP® for example:

  • In-RIP imposition is performed during interpretation
  • Color management (Harlequin ColorPro®) and calibration are applied during interpretation or compositing, depending on configuration and job content
  • Screening can be applied during rendering. Alternatively it can be done after the Harlequin RIP has delivered unscreened raster data; this is valuable if screening is being applied using Global Graphics’ ScreenPro™ and PrintFlat™ technologies, for example.

A DFE for a high-speed press will typically be using multiple RIPs running in parallel to ensure that they can deliver data fast enough. File formats that can hold multiple pages in a single file, such as PDF, are split so that some pages go to each RIP, load-balancing to ensure that all RIPs are kept busy. For very large presses huge single pages or images may also be split into multiple tiles and those tiles sent to different RIPs to maximize throughput.

The raster image processor pipeline. The Harlequin RIP includes native interpretation of PostScript, EPS, DCS, TIFF, JPEG, PNG and BMP as well as PDF, PDF/X and PDF/VT, so whatever workflows your target market uses, it gives accurate and predictable image output time after time.
The raster image processor pipeline. The Harlequin RIP includes native interpretation of PostScript, EPS, DCS, TIFF, JPEG, PNG and BMP as well as PDF, PDF/X and PDF/VT, so whatever workflows your target market uses, it gives accurate and predictable image output time after time.

Harlequin Host Renderer brochure

 

To find out more about the Harlequin RIP, download the latest brochure here.

 

This post was first published in June 2019.

Further reading:

1. Where is screening performed in the workflow

2. What is halftone screening?

3. Unlocking document potential


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Choosing the software to drive your digital inkjet press

When developing your first or next digital press, the software you use to drive it will be a key factor in its success, both for the data rates and output quality you can achieve. The time it takes to get your press to market based on the engineering effort involved to deliver and integrate that software is also a consideration.

A simple user interface to get  you started

The Press Operator Controller (POC) is an example front end or user interface available with Harlequin Direct™ , the software solution that drives printhead electronics at ultra-high data rates while retaining high output quality. The POC provides you with an initial working system, so you’re up and running without any significant in-house software development. We provide you with the source code so that you have the option to update and integrate it as part of your production system.

I have created a short video to show you its main functions:

You can find out more information about the Direct™ range of products by visiting our website: https://www.globalgraphics.com/products/direct

Further reading about considerations when choosing your digital inkjet press:

  1. How do I choose the right PC specification for my digital press workflow
  2. Future-proofing your digital press to cope with rising data rates
  3. Looking to reduce errors with simple job management, keep control of color, and run at ultra-high speed for jobs with variable data?

About the author

Ian Bolton, Product Manager, Direct
Ian Bolton, Product Manager – Direct

Ian has over 15 years’ experience in industry as a software engineer focusing on high performance. With a passion for problem-solving, Ian’s role as product manager for the Direct range gives him the opportunity to work with printer OEMs and break down any new technology barriers that may be preventing them from reaching their digital printer’s full potential.

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