G7® Grayscale Compliance:
This is the fundamental level of G7. Regardless of printing technology, if we can ensure that a printer or press prints the neutral tone ramp well, then all other colors will tend to fall into line more easily.
Grayscale is the level that we are used to seeing. A target print is printed on a stable printing system and measurements of that target are used to correct the ink curves to bring the printing system into alignment with the G7 ideal neutral density curve.
Aligning the printing of various printing methods in a plant to this same neutral aim point is a tremendous step forward in getting these disparate printers to match. While achieving this G7 level will naturally help all the colors to be consistent, the only thing that is required at this level is for the K and CMY neutrals to be aligned to the G7 tone curve and the CMY neutrals gray balanced.
G7® Targeted Compliance:
This is a secondary level of G7 and G7 Targeted is achieved when G7 Grayscale is achieved, plus the solid ink measurements for primaries and secondaries (CMY and RGB) and substrate color are also within spec to one of the G7-based TARGETED color spaces.
This can be achieved according to the absolute white point or using substrate-relative condition. G7 Targeted compliance is not limited to only the reference print conditions in ISO 12647-2 or in ISO PAS 15339, any G7-calibrated dataset can be used as G7 reference print condition.
Those who want, can use their own color reference in place of the standard CRPC’s, but their files must be verified as being compliant with G7 Grayscale.
G7 Targeted achievement lets customers know that not only can a facility hit G7 Grayscale, but they can also achieve a higher level of compliance and their strongest colors can hit, for example, the specific LAB values for GRACoL 2013.
G7® Colorspace Compliance:
This is the third level of G7 compliance and the most stringent. G7 Colorspace includes all the requirements of the G7 Targeted level (and therefore the G7 Grayscale level) and adds the matching to an entire Reference Print Condition. This level demonstrates that you are maintaining extremely tight tolerances throughout the whole color space. An entire IT8.7/4 target is compared against the targeted color space and the average of all the 1617 patches needs to be with a narrow range of tolerances. This assures that the printing system can consistently reproduce the entire color space and not just the primaries and secondaries (CMY and RGB).
G7 Colorspace can also be relative to either the absolute white point or the substrate-relative aim values.
G7 Colorspace level is also further divided into two separate purposes, Printing or Proofing. There are slightly more stringent requirements (tolerances) for proofing.