G7® is an Idealliance specification that defines a universal appearance for B&W imagery (or a printed grayscale), as well as how to calibrate and control any printing or proofing system to achieve that appearance. It is also the basis of GRACoL and SWOP, and the new CGATS.21 suite of Reference Print Conditions.

Ideal CMYK values can be calculated by simple formulae directly from CMY values, but these values are not accurate for colour printing (Ford and Roberts, 1998): Black (K) = minimum of C,M,Y Cyan CMYK = (C - K)/(1 - K)

The CMYK color model (also known as process color, or four color) is a subtractive color model, based on the CMY color model, used in color printing, and is also used to describe the printing process itself. The abbreviation CMYK refers to the four ink plates used: c yan, m agenta, y ellow, and k ey (most often black).

Validating Gray Balance (CMY scale only) To validate gray balance correction, the CMY-only scale shall be measured with a spectrophotometer and the a* and b* values recorded for each patch.

The RGB|CMY Digital Color wheel displays an entire color spectrum according to the RGB color mixing theoretical model. Around 1998, Bendito coined the title “RGB/CMY Digital Color Wheel” to highlight the major colors of the digital age: Red, Green, Blue, Cyan, Magenta, and Yellow.

Within this family of PressSync templates, desired Lab values for gray patches, paper, and solid are gray-balanced and calculated using the G7 calibration methodology. The templates below starting with G7_ include tolerances for ink solids and gray balance.

What Is the CMYK Color Model? The CMYK color model stems from four initial colors: Cyan, Magenta, Yellow, and Black. The most intriguing aspect of CMYK is that it is a subtractive color model. Essentially, with subtractive color, pigmented ink reduces the light typically reflected on the initial white paper.

An important by-product of the GRACoL project was the G7 specification which defined a “universal gray scale appearance” that can be applied to all printing systems, regardless of ink color, substrate or technology, and a simple calibration method for achieving it.

The "NPDC" ("Neutral Print Density Curve") displays separately for CMY (combined) and K (black). The G7 Specification defines standard grayscale curves that are used to create a neutral view of the output on different output devices.

CMY color model is a color model, used in color printing. CMY refers to the three inks used in printing: c yan, m agenta, and y ellow. The CMY model is subtractive. It means that it subtracts or masks colors from white background of the paper. The ink reduces the reflected light.