Author Archives: Paula Halpin

Channelling how many spot colors?!!

Recently my wife came home from a local sewing shop proudly waving a large piece of material, which turned out to be a “swatch book” for quilting fabrics. She now has it pinned up on the wall of her hobby room.

It made me wonder how many separations or spot colors I’d ever seen in a single job myself … ignoring jobs specifically designed as swatches.

I think my personal experience probably tops out at around 18 colors, which was for a design guide for a fuel company’s forecourts after a major redesign of their branding. It was a bit like a US banknote: lots of colors, but most of them green!

But I do occasionally hear about cases where a print company or converter, especially in packaging, is looking to buy a new digital press. I’m told it’s common for them to impose together all of their most challenging jobs on the grounds that if the new press (or rather, the DFE on the new press) can handle that, then they can be confident that it’ll handle any of the jobs they receive individually. Of course, if you gang together multiple unrelated jobs, each of which uses multiple spot colors, then you can end up with quite a few different ones on the whole sheet.

“Why does this matter?” I hear you ask.

It would be easy to assume that a request for a spot color in the incoming PDF file for a job is very ephemeral; that it’s immediately converted into an appropriate set of process colors to emulate that spot on the press. Several years ago, in the time of PostScript, and for PDF prior to version 1.4, you could do that. But the advent of live transparency in PDF made things a bit harder. If you naïvely transform spots to process builds as soon as you see them, and if the spot colored object is involved in any transparency blending, then you’ll get a result that looks very different to the same job being printed on a press that actually has an ink for that spot color. In other words, prints from your digital press might not match a print from a flexo press, which is definitely not a good place to be!

So in practice, the RIP needs to retain the spot as a spot until all of the transparency blending and composition has been done, and can only merge it into the process separations afterwards. And that goes for all of the spots in the job, however many of them there are.

Although I was a bit dismissive of swatches above, those are also important. Who would want to buy a wide format printer, or a printer for textiles, or even for packaging or labels, if you can’t provide swatches to your customers and to their designers?

All of this really came into focus for me because, until recently, the Harlequin RIP could only manage 250 spots per page. That sounds a lot, but wasn’t enough for some of our customers. In response to their requests we’ve just delivered a new revision to our OEM partners that can handle a little over 8000 spots per page. I’m hoping that will be enough for a while!

If you decide to take that as a challenge, I’d love to see what you print with it!

Meet the team behind Fundamentals

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:

Srikrishna Nudurumati

Srikrishna Nudurumati, Colour Scientist at Global Graphics Software

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.

About Fundamentals

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.

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 for more information.


Fancy a test drive of the new Harlequin v11 at drupa 2016?

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.

Preparing for the Inkjet Conference 2015

Making progress in half-tone screening technology – our samples are ready to display!

We’re really looking forward to the Inkjet Conference in Düsseldorf next week. Global Graphics’ CTO, Martin Bailey, will be speaking at the conference and focusing on the problems inkjet vendors have encountered when printing on high-speed inkjets, particularly with regard to optimum image quality and droplet placement.

With this in mind, for the last few months we’ve been working with a number of inkjet press manufacturers to develop entirely new half-tone screening technology for presses that can vary the amount of ink delivered in any one location on the media. We’ve just received our sample prints to show you at the Conference and we’re really pleased with the results – you can see the improvement immediately.

The samples show typical ‘before and after’ scenarios: The ‘before’ samples are quite noisy and show mottle and puddling; the ‘after’ samples, printed with Global Graphics screening technology, show much smoother gradients where we manage the transition of droplet size in multi-level heads.

We have also prepared sample prints showing what the output looks like with no tuning on: They show noise and steps in gradients for multi-level output, then we demonstrate what happens when we use transition points of drop size when using inks such as white, orange and violet in the colour spectrum.

Look out for Martin at the Conference and drop by our table in the IJC Networking Arena to see the prints for yourself.

If you are interested in the benefits of half-tone screening on high-speed inkjets and would like to join our research programme, watch our video here for more information:

Alternatively, contact Martin Bailey directly:

Read Martin’s abstract here:

New Flexo screens give premium print quality

HXMFlexo screens

Bump up curves in Harlequin’s new flexo screens help pre-press operators achieve smooth gradations even in high-key images.

Our Harlequin product team has launched a set of hybrid screens specially developed to give premium quality in flexo work.

The screens address the well-known issues of how to achieve high-quality in the highlight areas of images, such as tones close to white or skin tones, and how to print those areas with smooth gradations.

“We used the Harlequin Cross Modulated™ screens as the basis for development and have expanded the number of screens and included a mechanism to auto select calibration that goes with a particular screen,” comments Martin Bailey, CTO, Global Graphics.

“With the new Harlequin Cross Modulated Flexo (HXMFlexo) screens you can produce high-quality graphical objects by selecting from a wide choice of screen resolutions, rulings and dot sizes. Pre-press operators also now have the ability to bump up curves at the highlight end to compensate for flexo not being able to produce tones close to white clearly, so you can achieve smooth gradations even in high-key images.”

The new screens are the result of working with our OEM partners in the flexo market who have used the Harlequin RIP for years and we’ve been able to take input from a variety of vendors to fine tune our plans.

HXMFlexo works with the latest editions of the Harlequin RIP.