Colour science and “printing to the numbers” is critical to providing consistent quality in the graphic arts industry. It is widely understood that colour reproduction must be accurate and that colour management systems help provide reliability. Reinventing the (colour) wheel for every printing job is time consuming, stressful and an unnecessary practice, especially with the technology available today.
However, already complex colour management issues can become even more convoluted as offset and digital technologies meld together under one roof. In order for a printer to offer one-stop-shopping for both digital and offset production, colour consistency is required across both technological platforms. Therefore, as the digital printing market continues to grow, colour management systems that enable digital presses to match their offset counterparts are increasingly necessary.
In light of this trend, IDEAlliance (International Digital Enterprise Alliance) has developed a useful Digital Press Certification program to assist with understanding whether or not digital press systems can manage colour to the same degree as their offset counterparts (based on GRACoL specifications).
IDEAlliance Digital Press Certification
IDEAlliance is a third-party standards provider in the graphic arts industry who recognized the need for certification of digital press capabilities. In response to this need, they established the IDEAlliance Digital Press Certification program for commercial production xerographic and inkjet presses. This testing and certification encompasses colour, print properties and print production, while taking into consideration the entire press system (including the Digital Front-End, print engine and paper). In essence, the Digital Press Certification program is equivalent to what GRACoL and SWOP are for inkjet proofing, but for digital presses.
In order to obtain the Digital Press Certification, digital press suppliers are provided with a series of test forms to print according to given criteria. A designated research laboratory then measures the printed forms against pre-determined tolerances. Once a digital press system is certified, that certification is valid for the lifetime of the system.
Since launching in 2011, there have been 13 systems certified from major suppliers including Konica-Minolta, Canon, Xerox, HP and Ricoh. The systems use different controllers or DFE including Fiery, Creo, FreeFlow, SmartStream, etc.
IDEAlliance clearly identifies that certified digital press systems “meet or exceed established industry tolerances for excellence in the areas of Colorimetric Accuracy, Uniformity, Repeatability, Durability, and Registration, and are therefore officially awarded IDEAlliance Digital Press Certification.”
GRACoL
One of the first technical tests performed in the Digital Press Certification process is to confirm how closely the digital press system can match the GRACoL (General Requirements for Applications in Commercial Offset Lithography) colour characterization data. Using GRACoL specifications, any printer anywhere in the world can create the GRACoL “look and feel” on inkjet proofers, monitors, offset or digital presses. This specification helps to establish consistency when there are so many variables across printing processes, front-end systems and operators.
GRACoL establishes “printing to the numbers” by using the CMYK GRACoL control strip and list of target L*a*b* values for each patch. A printer can establish a colour managed workflow and then print and measure the control strip to ensure that their L*a*b* values match the specified L*a*b* values. If the numbers match the required values, they can be assured that they are meeting the GRACoL printing condition, and as a result, their images will look the same as anyone else meeting the GRACoL printing condition.
To accurately replicate colour originally printed on an offset press (using GRACoL specifications) and reproduce it on a digital press, two ICC profiles must be used:
1. The GRACoL source ICC profile is used in the digital press system’s Digital Front End (DFE)
2. The desired press destination ICC profile is used to replicate colour reproduced in offset
Dr. Abhay Sharma, Professor at the School of Graphic Communications Management at Ryerson University, has conducted extensive colour management research across North America, including Digital Print Forum studies for the International Digital Prepress Association (IPA). Dr. Sharma further explains GRACoL in his report called Digital Production Printing – Certified!:
The output will look very similar on all devices [if] everybody uses the freely available GRACoL ICC profile as their source profile and then their device destination profile – the inkjet proofer, digital press or monitor. Everybody just prints or proofs to the L*a*b* numbers specified in the GRACoL Guidelines and Specifications, and an output looks similar.
With regards to reproducing the GRACoL print condition on a digital press, Dr. Sharma states that “the IPA Digital Print Forum studies have shown that on 100lb text stock, the digital press gamut is generally big enough to match the GRACoL print condition.”
The image below is from Dr. Sharma’s Digital Print Forum studies. It depicts the GRACoL colour gamut paralleled against the CIELAB colour gamut of several digital presses. The graphic suggests that the gamut of most digital presses is similar to GRACoL (100 lb. text paper was used in this test).
Additionally, Dr. Sharma reminds us that, “everything is available as a free download from the IDEAlliance (Guidelines, data files, ICC profiles and CMYK Digital Control Strip). These tools and this way of working makes GRACoL one of the most useful colour management tools in offset and digital printing today.”
IDEAlliance Digital Press Certification: Suppliers and Users
You may be thinking to yourself, “Third-party certifications make sense, but does the IDEAlliance Digital Press Certification directly affect me?”
The answer is “yes” and it affects both digital press suppliers and users – here’s how.
If you are a digital press supplier this certification affects you because it can help you remain competitive in the marketplace. Customers can have greater confidence knowing that they are purchasing a certified system with colour and press capabilities that meet or exceed industry tolerances. Once your system is certified, you can use the Digital Press System logo in your marketing material. Additional visibility is also generated as certified system details and supplier logos are published in IDEAlliance’s website (found here: http://bit.ly/ptDXCt).
If you are a digital press user, this certification can help you better understand the capabilities of the array of digital press systems available. Although this certification is certainly not the only factor to take into consideration when sourcing a digital press system (price, service and workflow integration needs must also be considered), it provides guidance and reassurance that it is third-party verified. It also helps you understand whether or not a digital press system is able to match the gamut of GRACoL, and therefore if it can be integrated effectively into your current offset offering. Lastly, the third-party certification encourages suppliers to continuously improve their technologies.
It is critically important to understand how colour is reproduced on both digital and offset press equipment, especially if they are both part of your service offering. Third-party certification programs, like the IDEAlliance Digital Press Certification program, are great ways to demonstrate the quality and integrity of your digital press system’s colour reproduction capabilities. Colour management specifications like GRACoL help print providers simplify and standardize quality colour printing across a range of devices.
