G7

Since version 18.1, MeasureColor is capable to analyse if a print complies to IDEAlliance G7.
MeasureColor is capable of checking both G7 'Grayscale' (NPDC) and G7 'Targeted' (NPDC + solid/overprint colorimetric values).

requirements for use of G7 in MeasureColor

  • a color bar that meets G7 requirements
  • a color book that includes your process reference colors
  • a tolerance set that includes the G7 metric

creating a G7 compliant Color bar

A G7 Color bar should have at least the following patches:

description patches colors MeasureColor patch properties
All process ink solids 4 C/M/Y/K C:100/M:100/Y:/100/K:100
25% tints for each process ink 4 C/M/Y/K C:25/M:25/Y:25/K:25
50% tints for each process ink 4 C/M/Y/K C:50/M:50/Y:50/K:50
75% tints for each process ink 4 C/M/Y/K C:75/M:75/Y:75/K:75
G7 Highlight (HC) 1 C:25, M:19, Y:19 BHG7
G7 Mid tones (HR) 1 C:50, M:40, Y:40 BMG7
G7 Shadows (SC) 1 C:75, M:66, Y:66 BSG7
Substrate patch 1 none PW
3-color overprint C+M+Y 1 C:100, M:100, Y:100 CMY100
2-color overprints 3 M+Y(100),C+Y(100),C+M(100) MY/CY/CM

selecting or creating a G7 compliant Color book

Using the Reference manager module, import your ICC profile to be used as Color target or select an industry standard GraCOL or ISO for your printing condition.

creating a G7 compliant Tolerance set

Create a new Tolerance set that includes these 'rules':

  • Solid Process color delta-E
  • Solid Spot color delta-E
  • Overprint color delta-E
  • Substrate color delta-E
  • G7

creating a G7 Job

In MeasureColor ProcessControl module create a new job using these detailed settings:

  • select the Printing Condition and substrate coming from your process reference set (the ICC profile described above))
  • select a Tolerance set that includes the G7 metric
  • select Measurement conditions that comply with your process
  • add the process inks from your ICC based Color book to the job
  • select a G7 compliant Color bar

Note: G7 can be combined with spot colors as well and using the new options in the Measurement conditions you can use SCTV for Spot Colors and G7 for your process colors.

After this, a G7 button will appear.

Note: When G7 is switched 'ON' in your job's Tolerance set, you cannot make use of the 'OK sheet' function in MeasureColor's ProcessControl module. Also, it is not possible to create CTP curves for G7 jobs.

analysing the measurements

To analyse if you meet the G7 requirements, open the G7 analysis view.
The G7 Analysis view has two tabs: Overview & NPDC.

G7 Overview


The G7 overview shows a summary of the Black and Gray patches (the G7 NPDC).
You can click on each of the patches in the list to see more details on how to optimize to meet/improve on G7 specifications. The overview is intended for G7 trained operators.

Basically, it either shows a proposed correction for Black tone values (apparent dot size difference) or the Gray balance correction needed to comply with G7 specifications (also apparent dot size).

The Substrate and Solids section displays information about the G7 'Targeted' state. It shows the ink solids and their state (OK/warn) and when you click on an item it shows the ChromaTrack information for optimum results (best match).

The overprint section displays the state of your 2-color and 3-color overprints.

G7 NPDC


The NPDC tab focuses on the G7 NPDC and it is intended for G7 trained quality managers.
The view includes the NPDC curves for Black and CMY (balance) as well as the weighted delta-L and weighted delta-Ch for each metric.

Other process control views that make use of G7 (if needed)

  • Ink zone Gray balance view
  • Gamut view
  • Dotgain view
  • Spot detail view

Ink zone Gray balance view

The ink zone Gray balance view automatically switches between generic balance functions and specific G7 NPDC functions. In case of G7, this view makes use of the mid-tone information, being the 50% K patch of the HR-balance patch (50/40/40).

The 3 bar graphs display 'brightness' differences, but translated into clear information for machine operators (density corrections). The HR Balance bar graph displays the proposed color correction in the mid-tone area, also in an easy to understand method for the machine operator (dot size + and -). The corrections are calculated using MeasureColor's 'GrayFinder' technology.

As with many views in MeasureColor, you always aim for the white line in the centre, if the bar is too high, you are too dark, if it points below the white line, you are too light.

Gamut view

The MeasureColor Gamut view also adapt to G7 metrics if needed. The items that display G7 specific information are the 'Tints' section and the 'Balance' bullseyes.

Tints

The 'tints' section automatically displays either TVI difference (spot colors) or tone value corrections for G7 (C/M/Y/K). The tone value corrections for C/M/Y are calculated using MeasureColor's GrayFinder technology.
the GrayBalance bulls eye graphs. The center of the graph is your G7 Neutral Gray, the blue dot(s) indicates the measured color cast compared to G7 neutral gray.

Bullseyes

(Also based on the dynamic References.)

Tone value view

As G7 does not specify targets for tone value, MeasureColor will not display TVI targets and tolerances for C/M/Y/K process inks a G7 job. For operator convenience, we do still display the measured TVI (either using Murray-Davies or SpotColorToneValue formulas).

Spot detail view

The Spot views also respond to G7 when needed. Normally, MeasureColor will display static reference (CIE-Lab color target) and delta-E information, G7 jobs will now show the dynamic G7 target values (G7 NPDC being relative to the substrate) and the weighted delta-L (Black and CMY) and weighted delta-Ch (CMY) values.

more information

For more information about G7, please visit these sites: