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International Color Standards, Part 2: Looking at Standards and their Meanings

(November 2007) posted on Mon Dec 03, 2007

Wading through all of the international standards for graphics printing can be a daunting task. Ruff's assessment of their purpose can help you better understand their value.

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By Mike Ruff

G7 is not the same thing as GRACoL 7. The G in G7 represents Gray Balance. The 7 is a symbol of the seven ink colors of ISO 2846 (CMYKRGB). The good news is there is no need for a G8, because the 7 is not a version of a specification. G7 is a calibration methodology that IDEAlliance developed to move beyond different color appearances and the obsolete thinking that we can’t make different line counts and substrates appear similar in print.

G7 targets ISO 12647-2, which also specifies the use of the ISO 2846 for process-ink colors. This calibration methodology is taking the offset industry by storm because of its simplicity and effectiveness in eliminating different appearances for different line counts and substrates. IDEAlliance is promoting the G7 method as a constant component of all future print specifications and has offered it openly for adoption by all standards associations for all types of imaging or media, worldwide. Consultants can become G7 Experts through training and certification and print companies can become certified G7 Masters.


Comparing the commonality

The key point to this explanation of standards and specifications is that ISO printing specifications should not be ignored. The commonality of all these specifications and standards is that all of them are links to two international standards: ISO 2846 for ink color and ISO 12647 for printing. We also learned that there are some obsolete appearance-based specifications in these print standards, based on our ability to now adjust TVI (dot gain) to make the different line counts look the same.

This fact became very obvious to the offset industry when IDEAlliance developed the G7 calibration methodology. Remember, G7 ignores the TVI specs and adjusts the gray balance to a specific value. But also remember they still link to the ISO ink-color and print specs. Therefore, if we ignore the line count and substrate variations, we can truly have a standard that all of our print devices can meet and be in a very close appearance to other calibrated processes around the world.

The tremendous benefit G7 presents to the print industry is simplified, real-world print values that target international standards. The target values can be easily understood and measured. If you measure it, you control it. Gaining control produces predictability, predictability produces productivity, and productivity produces profitability.



Mike Ruff is chief technology officer of Nazdar Consulting Service, Shawnee, KS. During his more than 35 years in the graphicarts industry, he has worked in the signmaking and screen-printing fields as both a manager and business owner. Ruff frequently lectures at trade shows, conducts training classes for the Screen Printing Technical Foundation, and authors articles for industry journals. He is a member of the Academy of Screen Printing Technology and is a Certified G7 Color Expert.



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