How does GMG OpenColor work? A unified approach to proofing and separation

GMG OpenColor is an advanced color management profiling software designed not only for highly accurate proof simulation, but equally for the creation of precise separation profiles. By building a spectral model of the actual printing condition, OpenColor ensures that proofing and production separations are based on the same physical reality — creating consistency from design to final print.

Spectral characterization as the foundation

At the core of OpenColor is a spectral characterization of the complete printing process — including inks, substrate, and press conditions. Instead of relying solely on traditional colorimetric models, OpenColor uses measured spectral data to calculate an accurate, process-specific color model.

The system creates an n-dimensional profile, where n represents the number of inks used in the printing process. For example, a 7-color expanded gamut workflow results in a 7-dimensional color space. This allows OpenColor to accurately calculate complex ink interactions such as:

• Overprinting spot colors
• Multicolor combinations
• Extended gamut printing (ECG)
• Special ink sets in packaging production

Color patches — including paper white, solids, tints, and overprints — are measured spectrally using a spectrophotometer. Measurement data can be captured directly within OpenColor or imported from third-party systems.

If measurement data is incomplete, the OpenColor Prediction Engine intelligently calculates missing values. This enables high-quality profile generation even from limited datasets, while additional measurements further increase precision.

Automated profile calculation

Profile calculation in OpenColor is largely automated. After entering measurement data and basic print condition parameters, the software computes the color model and resulting profiles without requiring manual curve adjustments.

Manual refinements remain possible, but they are not typically necessary. The goal is to model the physical behavior of inks and substrate as accurately as possible — not to “tweak” profiles artificially.

Proof profiles: accurate simulation of real printing conditions

OpenColor generates highly precise proof profiles that simulate real printing behavior, including complex spot color overprints and multi-ink interactions.

These proof profiles can be exported or automatically transmitted to GMG ColorProof. In an automated workflow, ColorProof can request a profile dynamically based on the inks used in a job. OpenColor calculates the required profile and sends it back, enabling fully automated proof production without manual intervention.

The result is a proof that reflects the true spectral behavior of the target printing process — particularly critical in packaging and label production.

Separation profiles: from color model to production optimization

A key advantage of OpenColor is that the same spectral characterization used for proofing also serves as the foundation for separation profile creation.

This ensures:

• Consistency between proof and production data
• Accurate ink behavior modeling during file conversion
• Reliable spot color handling and ink optimization

Separation profiles created in OpenColor can be used in GMG ColorServer, GMG ColorPlugin or third-party software. These profiles enable optimized color conversions tailored to the exact printing condition — whether for offset, flexo, digital, or multi-ink processes.

By basing both proofing and separations on the same spectral model, OpenColor eliminates discrepancies between simulation and production data. Designers, prepress operators, and printers work from a unified and physically accurate color definition.

One data set – two critical applications

The strategic strength of OpenColor lies in its integrated approach:

• One spectral characterization
• One accurate multi-dimensional color model
• Profiles for both proofing and separations
• Automated integration into production workflows

This unified methodology ensures maximum color fidelity, process stability, and efficiency — especially in complex packaging environments where spot colors, overprints, and extended gamuts are standard.