Wide-format Graphics: The G7 advantage for sign shops

by all | 23 March 2015 10:29 am

By Mike Ruff
In recent years, an increasing number of wide- and grant-format inkjet printing professionals have recognized the value of the G7 method for process colour imaging and have committed to getting their shops qualified as G7 master printers. They understand the advantages of calibrating their production department’s cyan, magenta, yellow and key/black (CMYK) imaging devices to ensure a visual match, with colour accuracy to each graphic file on the first print.

The primary productivity killer in many inkjet graphic production facilities is the need to make colour adjustments on the press. With G7, however, sign shops can show clients they are ‘in balance’ on the press and can print to a known arrival point with confidence, eliminating most subjective colour tweaking.

“Prior to G7, we were spending at least 30 extra minutes on a job where the customer wanted us to hit their colours,” says Mike Quigley, vice-president (VP) of Sign-Age, which produces grant-format inkjet graphics. “Reprinting to a previous graphic was even worse. We handle a lot of fleet graphics, for example, and customers frequently come to us after a vehicular accident with 
a request to replace only one section of their wrap. 
In the past, it was not unusual for us to spend three to four hours trying to get a colour match. Now, using G7 tools, we spend less than 15 minutes.”

It is easy to see how such time savings could add up dramatically and, hence, why every sign and digital graphics shop can benefit by using G7.

Free and independent
Invented by independent colour management consultant Don Hutcheson and published by the International Digital Enterprise Alliance (IDEAlliance), G7 is both (a) a definition of greyscale appearance and (b) the calibration method for adjusting CMYK devices to simulate that definition. It is device-independent, offering the same neutral print density curve (NPDC), grey balance definitions and calibration methodology for any imaging technology, regardless of substrate or colourants.

IDEAlliance, which governs G7 training and use, is a non-profit industry association that guides and publishes specifications and standards for the printing industry. Its primary purpose is to facilitate a level playing field 
for all stakeholders in developing and advancing best practices. As such, 
it cannot endorse any particular technology over others.

G7 can be implemented and used for free, without buying additional hardware and software. G7 spreadsheets, graphs and 
other information are available 
on IDEAlliance’s website 
(www.idealliance.org).

That said, some software, raster image processors (RIPs) and related equipment have made G7 easier and faster to use. A self-calibrating machine, for example, can be combined with pass/fail software to make the process more efficient. There are many such systems for calibration and control, which IDEAlliance also lists on its website.

Controlling the process
In digital inkjet printing, G7 is mostly used to achieve a neutral grey starting point for colour management, which improves accuracy to targeted print specifications. It helps by calibrating the grey balance of non-standard substrates and inks.

G7 itself is not colour management, nor does it even 
have to be used with colour management, but in inkjet print production environments, it is most commonly implemented with colour profiles. Indeed, many inkjet devices and RIPs now use G7 to provide a common starting point for the use of International Color Consortium (ICC) profiles.

The trend today is for clients to send a Portable Document Format (PDF) file of their desired graphics, not hard-copy proofs, which has sometimes made it difficult for signmakers to know if their prints are accurate to what their customer wants. G7 provides the methodology (a) to be accurate to the file and (b) to be able to prove that accuracy in a measurable way.

The measurable point of reference is colorimetric neutral grey balance, which proves no unwanted colour cast is added to the file. Figure 1 illustrates what major print buyers have to deal with when purchasing inkjet-printed graphics after not supplying a hard-proof guide; the leftmost image is accurate to the file, indicated by the neutral grey bar, while the other four images are typical results from non-G7 print shops. The colours in these images may still look good in isolation, with no comparative hard proof, but if the client were selling golf sweaters, then these prints would more than likely be rejected for not representing the products realistically.

G7 provides a solid, indisputable point of reference for file reproduction. This does not mean customers will never again want to adjust colours, but there is now a high likelihood they will accept the logic of G7’s accurate results. They should be happier and more loyal when they can trust the results.

Another way to think of G7 is as ‘process control,’ given it provides base calibration before ICC profiles 
are applied.

“When we talk about colour management, we tend to talk about instruments, neutral balance and colour difference values,” says Christopher Brown, engineering manager for wide-format printer vendor Mutoh America, “yet when colour management fails, we tend 
to blame the hardware, software or operator. While software, instruments and well-trained operators are all important aspects of the workflow, colour management must be built on 
a solid foundation of process control to be effective.”

This distinction is important, as one common misconception suggests ICC provides grey balance and, therefore, G7 adds no value to calibration so long as ICC profiles are used.

“In most cases for inkjet applications, G7 calibration can simply replace conventional linearization, avoiding the need to add another step to the colour workflow,” Brown explains. “Rather than linearizing the printer in the conventional way, which has the effect of calibrating the printer only to itself, G7 calibrates the printer to a set of system-independent aims derived from the native white and black points unique to the printer, ink and media. The number of patches necessary to calibrate the printer need be no more than the typical number used for linearization. It requires no more time nor expertise and the resulting curves can be applied in the same way as conventional linearization curves.”

Fostering calibration
G7 is solving problems in inkjet print production that other printing technologies have not addressed. 
The primary market advantage of digital inkjet printers is they can efficiently produce short runs of graphics on a broad variety of substrates, using inks with non-standard colourants. This advantage, however, can also be a disadvantage.

Most of the time, digital inkjet printing can mix light cyan, light magenta, light key/black and even orange and green inks with standard CMYK colourants to achieve the targeted image result. With so many non-standard elements, however, colour management is very important in guiding such results or the graphics will be a mess. Fortunately, once a neutral grey aim point is specified, it is possible to mix all of the colours to achieve 
base calibration.

When a client sends an image to be inkjet-printed, 
he/she may have spent many hours correcting that image to exactly the colours he/she needs simulated in the print. So, if the printer adds its own colour cast to the image, the client will not be happy. In the past, sign shops offered excuses like, “We can’t make it any better because of the substrate,” or, “We can’t match the image because we use six colours of ink, not four.”

By starting with G7 calibration prior to colour profiling, on the other hand, it becomes possible to establish a common baseline for grey balance and tonality and even ensure two or more printers produce very similar results.

Mastering the methodology
A G7 ‘master printer’ is a company, not a person, and the title does not represent certification, but rather ‘qualification.’ This involves a G7 expert—who has been trained and certified by IDEAlliance—visiting the company and documenting how it understands and performs G7 calibration of its equipment, including adjustments for substrate and colourant differences.

Some sign shops resist becoming qualified because they do not receive any requests from their customers for G7. This is missing the point, however. G7 improves productivity and accuracy in print production so as to increase profits on existing product sales. The customer need not know it exists.

Nevertheless, G7 can also offer a sales advantage. Some clients know about it and are starting to ask their print service providers (PSPs) if they are G7-qualified.

Even beyond these clients, G7 can be a powerful ‘closer’ in sales calls when sign shops are trying to acquire accounts for clients who are very demanding of accurate printing results, such as major fashion and food retailers. Explaining the G7 advantage can mean the difference between landing these accounts or seeing them go to a non-G7 competitor.

With this in mind, G7 master training and qualification can be followed by G7 sales training. This will help 
sign shops’ managers and other key personnel better understand how to inform clients about their use of G7 during sales calls.

It is common, after all, for demanding clients to ask, “What makes you different from the other shops?” 
And if the only answers are quality, service and pricing, the customer may sense an echo of other competitors’ promises. If on the other hand the answer is, “We’re a G7 master printer,” and the client asks what that means, then there is a major opportunity to stand out from 
the pack.

Here is how that conversation will typically go:

Salesperson: 
“
If you submitted your graphic file 
to three other vendors, would their resulting prints match?

Print buyer: 
“No.”

Salesperson: 

“
So, if they are different, but all of them 
look pretty good, which one is accurate 
to your file?”

Print buyer: 
“There’s no way to tell.”

Salesperson: “
Actually, there is. Our company is a G7 master printer, which means we print to neutral, without adding a colour cast to your file. Our equipment and workflow are neutral. Using the G7 methodology, the prints we produce will be the most accurate reproduction possible of your file. This is why you should buy from us.”

If the salesperson can then show two samples of the same image, one grey-balanced and one not, along with a G7 colour bar on each print, then the client will see and understand the difference. And this is not only important with new prospects; existing clients will also care very much about accuracy.

Changing the world
Major print buyers are further driving the adoption of G7. Their challenges of time to market and shipping costs have motivated them to source graphics from G7 master printers in different regions. Previously, they could not do so with confidence, as different printers using different inks on different substrates did not result in a common visual appearance. It was certainly possible to achieve great-looking prints, but very difficult to match them.

Now, on the other hand, these buyers know G7 master printers use the same calibration points, adjusted colorimetrically to an NPDC, and can therefore produce a common visual appearance anywhere across the world, regardless of inks and substrates. Graphics can even 
be matched across different printing methods, such as digital inkjet and screenprinting.

As such, another growing trend is compliance to international standards. American National Standards Institute (ANSI) and Committee for Graphic Arts Technologies Standards (CGATS) 21-1 and 21-2, Graphic technology – Printing from digital data across multiple technologies, for example, are print standards based on G7. General Requirements for Applications in Commercial Offset Lithography (GRACoL) and Specifications for Web Offset Publications (SWOP) are also based on G7’s NPDC. The International Organization for Standardization (ISO) is lagging behind somewhat, due to small pockets of resistance to the colorimetric print standards established by G7, but ISO/TS 10128:2009, Graphic technology—Methods of adjustment of the colour reproduction of a printing system to match a set of characterization data, provides G7 as a grey balance calibration option. And as mentioned earlier, colour management tools, RIPs and graphic design software are all adding features based on G7 and standards for grey balance.

All of these changes will affect wide-format printing professionals whether they know it yet or not. Their companies stand to benefit by becoming qualified as G7 master printers now, rather than later, as they will be positioned to comply with new standards for colour accuracy as they come into effect.

Mike Ruff is a consultant with more than 40 years’ experience in the graphic arts industry, chair of the Academy of Screen and Digital Print Technology (ASDPT) and a certified G7 expert trainer. He is scheduled to present a seminar at Graphics Canada 2015 focusing on best practices for profitability. For more information, contact him via e-mail at mruff@mikeruffconsulting.com and visit www.graphicscanada.com.

Source URL: https://www.signmedia.ca/wide-format-graphics-the-g7-advantage-for-sign-shops/

---