Conventional ICC-based colour management is effective in the standard CMYK printing world, such as the commercial printing market. However, in the packaging printing market, where spot colours are regularly used and there’s been no solution for this until now, spectral could be the answer. This article will show why this is so, summarise the key benefits of working with CxF data, and explain how spectral CxF data can easily be used throughout the entire production process – from design to print.

Initially, it may seem cumbersome when you explain to printers that their daily business will be simplified by implementing spectral data as a cornerstone to their colour workflow environment. The concept may seem complex. Until now, the CxF open standard has been in the early stages of true adoption, and we still find some resistance to change. This fear is natural, but it can also enable companies to be more profitable when they embrace new technology advancements.

The colour exchange format (CxF), which is the basis for spectral colour data, is discussed in many expert industry forums related to colour management. This is for good reason, and it’s already referred to as ‘the silver bullet to communicate and manage colour’.

Let’s explain why and introduce you to some new features which make working with spectral data simple and help boost the overall efficiency of your business.

Advantages and potential of spectral data

A huge advantage of capturing CxF colour data is that all characteristics of the colour are included and easily communicated. This sounds simple, right? But if you take a good look at the daily business of many companies, you will see that many members of the graphic arts industry are struggling with challenges around a lack of complete or insufficient colour data. They usually receive this data from their clients or may provide it to their suppliers.

To communicate colour effectively, it is not enough to describe the solid tone value as is done in most cases today. You need to include all the aspects of a colour, such as the halftones, and even the overprinting behaviour. Ultimately, this is crucial information as spot colours are used not only for solid brand colours but also separation colours. This includes halftones and gradations. Moreover, these separation colours may be overprinted with each other.

This is of great importance for packaging, to secure brand identity and colour consistency. With spectral data and suitable tools, you can easily do this.

Why spectral?

Brand colours, often expressed as Pantone colour names, are generally specified using CIE Lab values. The Lab value describes how the spot colour looks under certain lighting conditions (D50). It does not describe how the midtones should behave nor provide any information about what the colour looks like under other lighting conditions. This lack of lighting information may cause metamerism, a phenomenon where colours look different when light source changes.

To maintain global colour consistency, brands are using CxF/X-4 (colour data exchange format part 4, registered as ISO 17972-4:2015) to communicate colours. CxF/X-4 allows colours to be communicated using spectral data, including midtones and ink opacity information. This additional data is used to calculate colour differences under various lighting conditions, not only on the solids but also the midtones and overprints (or mixture of multiple colours).

Analogue to Digital

Today, CxF is mainly used in conventional (or analogue) production printing. Printers use the CxF data to blend inks and verify colour differences in optical wavelength.

Some products (print jobs) originally designed for analogue printing production are sent to digital printing. This may occur as a repeat production in a smaller run, and versioning for different variations, etc.

When these jobs are sent to digital printing production sites, print operators may face difficulties matching colours against print samples from an analogue press. If the design contains midtones or spot colour overprints, it may be nearly impossible for the operator to adjust print settings (such as tone curves or colour correction table) to get an optimal result.

However, if the print job is sent as a CxF embedded in a PDF to a CxF-aware DFE (such as SCREEN’s EQUIOS), the print operator should deliver an optimal result from the first output without needing cultivated operator skills.

This, of course, does not mean that the digital press will increase its colour gamut by using CxF. For the digital press to achieve equivalent result to the analogue press, the design must use colours within the digital press’s colour space. The DFE will find the best colour combination using the fixed colour sets used by the digital press to express spot colours defined by CxF.

Working with CxF data is simple

There are still many reservations in the market around the adoption of CxF data. In our experience, this is often related to the uncertainty of how to manage CxF data, the benefits, and how to go about implementing a CxF-based workflow. People are often under the impression they will need a lot of time to create the initial CxF data, which is necessary to get started. In some cases, they are right. In the commonly used, conventional way, it is time-consuming, as you need to create, print and measure CxF tint ramps for all the individual colours you need to work with.

CGS ORIS & SCREEN

CXF TOOLBOX technology is a user-friendly solution developed to minimise the burden and maximise the benefits and advantages of working with CxF. To combine the original CGS ORIS technology and SCREEN’s unique EQUIOS technology, SCREEN simplifies the user’s operation even more, and offers the turnkey solution for the Truepress Jet L350UV SAI.

Embedding CxF to PDF

EQUIOS DFE with the CxF option includes a licence for CXF TOOLBOX and CXF CLOUD from CGS ORIS. CXF TOOLBOX is used to create and embed CxF data to PDF. CXF CLOUD is an online database to share CxF data among multiple sites.

Creating CxF

To create a CxF data for a spot colour, a special chart must be printed on the target analogue press using standard printing process.

The chart consists of tint ramp over white and 100% pre-printed black for opacity calculation.

By measuring and evaluating the 100% solid patch’s spectral data with CXF TOOLBOX, printers will be able to adjust the spot colour ink at ink dispensing system.

Once the solid is certified, measure the other patches in the tint ramps and fill in the CxF/X-4 metadata fields (colour name, substrate, etc.) before saving or uploading to the CXF CLOUD.

These steps must be repeated for all colours on all printing processes (target device and substrate).

Creating CxF, the easy way

Printing and measuring the 22 tint ramps for every colour on every print process can be expensive and time-consuming.

CXF TOOLBOX comes with a new feature to simplify these tasks. SCREEN and CGS ORIS have jointly developed this technology that predicts halftones from limited colorimetric data. It uses a proprietary algorithm and automatically generates complete CxF data.

If you select the appropriate and stable printing process, the prediction should provide a reliable result.

Fetching CxF from the Cloud

If the CxF data is ready and has been loaded to the CXF CLOUD database, you can download the data and skip the cumbersome tasks needed to prepare the CxF to be embedded to the PDF.

Via the CXF CLOUD platform, brand customers and printers can create the same colour result environment among multiple sites. It guarantees access to complete colour data – always up-to-date and available for authorised users at any time and any place in the world.

Embedding CxF to PDF

Once the CxF data for a specific job is ready, it can be embedded to a PDF. To achieve a good colour match against overprint, you should specify the ink laydown order used by an analogue printing process.

Reproducing Brand Colours with EQUIOS

EQUIOS will process a PDF with CxF embedded using the spectral data for solids and midtones, as well as opacity and ink laydown information provided in the previous step. It will calculate a best colour match for the SCREEN’s digital inkjet press, the Truepress Jet L350UV SAI.

Summary

Working with CxF data and the newly developed prediction feature makes it easy to enter the beneficial world of spectral data. It offers much greater accuracy and security (as colours are captured with all their properties and behaviour), and helps production work become simpler and faster.

The experience of one large brand customer, for example, shows a saving of a month per year in the product innovation cycle. This, of course, leads to huge cost reductions.

Spectral data helps reduce errors (during the production process and between project partners). It ensures colour data is always up to date, and provides a timeless, durable and reliable benchmark, which does not shift over time like colour cards/chips. It offers several solutions to challenges, and helps to dissociate processes from individual colour experts within a company.

Because CxF is an open standard and can be applied to each printing process and varying substrates, it also ensures a high level of flexibility. This allows for a significant simplification of the entire colour workflow, translating into greater productivity and efficiency. This has positive knock-on effects for everyone in the production process, from design all the way through to end print production.

Working with spectral data and suitable tools guarantees consistent colour all over the world, wherever and whenever colour is printed. It removes the remaining challenge in the transition from analogue to digital printing. It also expands the opportunity for users to enjoy the latest ink jet technology in the growing demand for short-run and versioning/personalisation.

Choosing to invest in reelfed digital is a game changing decision for your business. Digital printing is the new technology proven to outperform sheetfed in speed, quality and ultimately profitability.

We believe that printing with digital technology will be the only viable choice when investing in new capital equipment, add to this the innovative SC inks the choice is obvious – but we’ll go into more detail on what the SC inks are later.

What’s the difference between offset and digital?

Digital is king – here’s why

Your handy guide on making the move from sheetfed to reelfed

Impassioned lithographers will make a hardened case for offset over digital. In the early days of digital printing, inkjet and the likes were considered glorified office printers. It was a fair assessment at the time.

But that was then, and this is now. In the near 30-years since its inception, this modern method of printing has come on leaps and bounds, greatly surpassing its clunkier offset cousin.

Digital printing still follows the same concept as a domestic inkjet printer but it’s much bigger, much faster and much more precise.

Whilst the creative journey of offset and digital differ massively, the finished product is indistinguishable to the untrained eye. Up until recently, offset’s biggest case against digital was economies of scale, with offset considered more economical for longer print runs. But SC inks has diminished that argument.

Now, deciding which route to go down lies more in process efficiency above all else. Again, it’s a battle that digital wins hands-down.

The Truepress 520HD with revolutionary SC ink technology

Setup and press make ready
Offset is seriously disadvantaged before production can even begin. In order to set up an offset print run, you need to prepare the plate – something that is both time-consuming and inflexible.

Once the plate is in place, it cannot be modified. The operator also needs to use “make ready” sheets to ensure correct colour balance and ink density. This process incurs a large material cost. Digital doesn’t have any of these problems because the image is created electronically and the printed image has the correct colour balance from the first sheet.

Turnaround
Without the need for plates, blankets and all the laborious setup time that comes with offset printing, turnaround time is shortened considerably. As a result, manpower is also reduced, saving money and time and allowing busy printers to realign resources elsewhere.

Changing information mid print-run
Furthermore, the simple setup of digital, allows for several versions of a printed item to take place in one print run. Dates and times, even images, are all things that can be altered mid-print job. This is simply not possible with offset. You’d have to stop the press, change the plates and start again.

Reduced maintenance time
As inkjet printing is contactless it comes with a host of other benefits, of which one is reduced wear and tear because of the absence of items such as blankets and packing sheets.

Variations in print
Offset printing relies on a delicate balance of ink and water, which inevitably results in inconsistencies in the final print. Digital printing doesn’t have this problem.

SC inks solve the ultimate printing puzzle

Previous limitations on inkjet printing have been detrimental to print quality, running costs, and return on investment. Inkjet-treated coated stocks remain significantly more expensive than untreated ones and likewise, pre-treatment of a more economic offset coated paper add to the cost and process complexity.

But SC inks have now eradicated this problem, enabling printers to use offset coated stocks in a digital press – more specifically, the Truepress Jet 520HD. And it doesn’t matter whether it’s gloss, matt or silk.

How you ask?

The Truepress Jet 520HD with SC ink incorporates revolutionary adhesive enhancements to ink, printhead control and screening, to allow printing on commodity coated papers at high speed with water-based inkjet inks. SC inks stand out due to their ability to preserve the texture of commodity paper with astonishing results.

SC ink brings together a host of benefits previously isolated to individual products, including:

• Greater expression using paper textures: SC inks maintain the integral texture and feel of coated paper, significantly expanding print application potential.
• Low cost solution with faster turnaround: Screen’s unique absorption technology cuts out the pre-processing stage, minimising times and cost whilst maximising economic viability.
• Photo like quality for print: SC inks also feature properties that include superior water, heat and light resistance, as well as a wide colour gamut that closely approaches offset types, making it very suitable for products such as coffee-table books for example.
• Printing on a wide variety of paper types: Printing is still also possible on a wide range of non-coated papers, including standard and specialised inkjet types. Thanks to this versatility, you can now use various paper types on the same press.

Find out more about the implications of reelfed printing here

Our brilliant engineers, through innovation, have unlocked the secret to efficient, sustainable inkjet printing directly onto standard offset coated stocks. The SC inks eliminate the costly pre-processing step, whilst sharpening the quality of printed content to offset standards! It’s the breakthrough moment that commercial sheetfed offset printers have been waiting for.

For sheetfed printers, it does require a migration in technology to web-fed digital printing – something that raises a lot of questions around the production process and the finishing.

In this blog we’ll highlight the core differences in more detail.

What’s the difference between reelfed and sheetfed printing?

As we all know, paper is manufactured in large rolls. The core difference between sheetfed and reelfed printing comes down to the way this paper is loaded into the printer.*

• In sheetfed, the paper is purchased sheeted in packs or pallets before printing.
• Contrastingly, reelfed printing uses a large roll which is then cut into appropriate sizing in the post press process.

Confused about the difference between offset and digital printing presses?

Describing it like this makes it look like a minor difference, but as you will soon find out, printing with reelfed has some pretty major implications – all positive.

The input side of reelfed:

1. It’s cheaper: it’s cheaper to purchase a reel than it is individual sheets. Why? Because the paper manufacturer avoids having to sheet it. You only have to check with your supplier to realise this can easily save around 10% in costs for standard offset coated paper – bingo!
2. It’s less wasteful: a reelfed production line makes it possible to eliminate printing gaps. This helps to use the paper most efficiently and can significantly reduce waste.
3. It’s easy to load: Surprisingly, feeding paper into a reelfed inkjet printer is relatively simple compared to sheetfed loading. Instead of loading a pallet of paper, you would hang the paper in a so-called unwinder – an easy-enough process. Depending on the paper weight, the length on a reel can vary somewhere between 7km equating to 11,784 A2 Sheets on 250gsm stock and a whopping 18km, equivalent to 30,303 A2 sheets at 70gsm.

Once in the printer, paper transportation is hassle-free. Unlike sheetfed, which relies on grippers and suckers, reelfed just consists of rollers and motors to control speed and paper path tension, as well as a device to keep the path precisely positioned under the printheads with sensors to monitor optimum stability.

To sum up, reelfed paper transportation is much less mechanical and more stable than sheetfed. This makes for a virtually hassle and maintenance-free process.

The output side of reelfed:

Output happens using a rewinder or an inline finishing device. Several years ago, the majority of printing operators chose to run the finishing offline. We’re now tending to see a change in behaviour, with inline becoming the preferred method as finishing technology grows ever more flexible and efficient.

More often than not, inline finishing from printed reel to finished product is a big question mark for sheetfed printers. Ultimately it’s in making the decision from sheetfed to reelfed, however, that the most efficiency is gained and here’s why.

• A physical collating step is completely removed, because your products are collated digitally. The easiest way to explain this is by using these examples:
  • 4 Colour Book: With sheetfed offset printing, all the book signatures will need to be printed before finishing can start. The printing of a 6-signature book will mean 6 print runs on the press, using 12 x 4 plates (48 Plates in total) and producing 6 pallets of paper. After that signatures need to be to be folded in a first step and collated in a second step, and both are extra touch points in production.
  • 4 Colour 16pp A4 Brochure: With sheet offset printing, again all the pages will need to be printed before finishing can start. The printing of a 16pp A4 Brochure using a SRA2 standard offetset press will mean 4 print runs, using 8 x 4 Plates (16 Plates in total), Section 1; 8 pages print front and then turn sheet to print reverse and then Section 2: 8 pages repeating process. Within off-line finishing, both sections will need to be pre-folded before passing through a stitch and trim line.

• Producing digitally from the roll does not require plates or setup time and the signatures are collated digitally per individual copy on the fly. Withinfinishing the pre-collated sets will be cut to sheets, folded and stacked to complete the bookblocks. No touch points – no risk – no over-production; increased profitability

Reelfed Speed Comparison

When it comes to reelfed the terminology is different. Sheetfed is monitored in the number of sheets per hour through the press whilst reelfed is calculated at number of metres of material per minute.

It is often difficult to quickly calculate the difference and this often makes reelfed look slow in comparison with sheetfed, however this is not the case, reelfed is often faster than sheetfed.

Now add in the benefit of in-line finishing and it is demonstrated that reelfed is superior to sheetfed in all “paginated” production.

Productivity (duplex sheets)

Common myths

Will your next press be a Truepress?

We come full circle, back to the aforementioned SC inks, which are used in the Truepress Jet 520HD+.

SC inks…

• Adhere directly onto a wide range of standard paper types, removing the need for costly pre-processing/coating.
• Maintain the integral texture and feel of coated paper. This significantly expands potential print applications to include direct mail, books, catalogues and a wide range of other commercial uses.
• Are completely dry when leaving the printer (which can operate at speeds from 120 to 150m/min)
• Offer a high colour gamut and sharpness, improved ten-fold because pigment is not lost in the absorption process

Our HD Digital inkjet printer has significantly improved the printing process whilst giving improved margin. Companies like Bluetree, Kohlhammer and Hubert & Co have chosen to invest in our continuous fed inkjet solution instead of a conventional offset press. Will you be next?

Find out more about the implications of migrating to digital printing here