G7 for High-Speed Aqueous Inkjet, Yes You Can!
The printing industry has always compared any new printing technology to the printing quality of offset. Ink sits on top of the paper surface with high color densities and minimal absorption.
Traditionally, measuring how well a technology matches to offset printing is based on a Delta E measure, averaged over several 1617 patch test targets called an IT8.7/4.
But how do you measure or control a process that does not have controlled ink color standards and print quality changes per OEM? A process in which the inks dry by absorption and are not ISO controlled.
G7 Gray Balance. Not to be confused with G7 Color.
Since we can’t control the color standards of the aqueous process ink colors, nor the densities, in most cases when using aqueous inkjet pigment and dye inks on inkjet on inkjet coated and treated papers, we can achieve neutral gray balance with different saturated or ink hues.
Because we see differences in gray more than more saturated colors, G7 Gray creates a closer visual "matching" to other printing devices than matching solid ink densities. This method is all about the gray balance.
HP, Canon Solutions (Océ), Ricoh and Screen high-speed aqueous inkjet devices all have different processes for profiling and controlling color. The G7 process is best utilized by entering the adjusted color curves directly on the machine (if possible) after uniformity and maximum density adjustment on the machine is complete, or applying the curves at the RIP. You can also apply as early binding using preflight software such as t-Flow Production Software, which allows G7 curve data adjustment directly to the .pdf previous to the machine. This is especially handy since making color and profiling changes on high-speed aqueous inkjet machines is quite tedious.
The goal of G7 Gray Balance is to create a visually consistent and repeatable neutral gray color.