G7® Curve Inspector &middot; Inspectors &middot; ChromaChecker

G7® Curve Inspector

ChromaChecker G7® Curve Inspector — analysing NPDC and HR curves for G7 compliance, verifying gray balance, and supporting G7 Master Qualification workflows.

G7 and Gray Balance

G7 is a press calibration specification developed by Idealliance that targets a perceptually neutral gray balance across the full tonal scale. Unlike TVI-based calibration, which targets individual CMYK channel curves, G7 targets the appearance of the combined print — specifically the Neutral Print Density Curve (NPDC) and Hue Rotation (HR) curves that describe how CMY gray behaves on press.

G7 Curve Inspector provides the measurement and visualisation tools needed to evaluate G7 compliance and to diagnose the root cause of gray balance failures.

Key Capabilities

NPDC Display

Plots the Neutral Print Density Curve for CMY and K channels against the G7 target NPDC — visually identifies regions out of tolerance

HR Curve

Hue Rotation curve shows the chromatic error of the CMY gray mixture at each density level — critical for diagnosing ink balance issues

A/B Analysis

Displays a* and b* values of the printed gray at each tonal step — G7 requires a* and b* to be within ±1.5 of neutral

Compliance Score

Pass/fail against G7 Grayscale and G7 Colorspace specifications — with zone-level detail (highlights, midtones, shadows)

Historical Archive

Compare current G7 compliance against previous sessions for the same device — identify calibration drift

Correction Guidance

Indicates which specific corrections are needed — CMY balance, K curve, or highlight/shadow adjustment

G7 Qualification Workflow

ChromaChecker supports the full G7 Master Qualification workflow:

Print the P2P test chart (P2P51) on press
Measure with Capture Inspector or any connected spectrophotometer
G7 Curve Inspector evaluates NPDC and HR compliance
If the press fails: export correction data for use in the RIP/CTP printing curve
Re-print and re-measure after curve correction
When all zones pass: generate a G7 compliance report for Idealliance submission

Note: ChromaChecker is an authorised G7 evaluation tool. G7® is a registered trademark of Idealliance. G7 compliance does not guarantee colour matching between devices without a common aim point.

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