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Expanded Color Gamut Implementation Study

INTRODUCTION

Expanded Color Gamut (ECG) printing is the process of using a fixed ink set to achieve the same result as with printing with spot color inks. The benefits of having faster make-ready, no spot color inventory, and exponential gains in efficiency has increased in popularity the past few years. By minimizing press wash-ups, reducing ink inventory, and eliminating the time associated with ink drawdowns and formulations, customers are become more efficient and profitable in the process of going the ECG route.

ADVANTAGES

Time Savings

Ability to ‘gang run’ multiple spot color jobs

Cost Savings

PREMISE

The purpose of this study is to analyze ECG printing method’s viability in multiple press types, as well as different ink configurations. We have chosen the PANTONE Coated library, and a color space coverage review completed on three different press types – digital (HP Indigo 15000), conventional (Heidelberg Speedmaster) and digital nanographic (Landa S10).

DIGITAL ENVIRONMENTS

14 Neon and Metallic colors were removed from the library, as no standard ECG ink set can cover these definitions.

Though industry standard allows for a delta-E of 5 and under to be ‘passable’, we opted to tighten the acceptance delta-E tolerance to between 2 and 3 for more real-life production requirements. Values within this tolerance is referred within this document as a spot color “match”. In this document we will also refer to this result as ‘inside’ the color space gamut, whereas an out-of-gamut result higher than a delta-E value of 3 would be referred as ‘outside’

An initial non-ECG press gamut coverage measurement was completed with only CMYK inks.

A 7-color (for instance, CMYKOGV, or CMYKOGB) ECG-ink set print run was then conducted and measured.

A 6-color (for instance CMYKOG, CMYKOV, or CMYKGV) ECG ink set print run was conducted and measured, if possible.

All conventional and digital press color separations were created, and automatically optimized using X GAMUT

A sample view of the PANTONE library processed through X GAMUT:

GAMUT COVERAGE FINDINGS

Below are color space coverage comparisons between a traditional CMYK print space and various ECG scenarios:

SUMMARY

Though a 7-color implementation is optimal and recommended (achieving, in all test instances in this study, a 92% and higher match of the complete PANTONE Coated library), in some instances a 6-color ECG configuration also achieved a 90% and higher match of this same spot color library.

Some important considerations:

Different ink manufacturers have different pigment mixes which can result in larger (or smaller) gamut sizes. In this study, on the digital/nanographic presses we used manufacturer-branded ink/toner cartridges (HP and Landa). Convention press ink manufacturer details can be furnished by contacting your CGS ORIS representative in your local region.
On conventional presses a 7-color ECG ink set would be preferred, although a 6-color setup is also achievable.
Conventional press implementations would depend on tight process controls (G7, SCTV control, and press maintenance, for example).
As different ink set combinations of a 6-color setup results in different areas of a color gamut for a good match for your use case (for example CMYK+OG versus CMYK+RB) we recommend contacting your CGS ORIS representative for a private consultation based on your facility’s existing spot ink library.

PANTONE Coated library and HP Indigo 15000 X GAMUT ECG Print Implementation
2149 colors (14 Neon and Metallic colors removed)

PANTONE Coated library and Heidelberg Speedmaster CD102 X GAMUT ECG Print Implementation
2149 colors (14 Neon and Metallic colors removed)

PANTONE Coated library and Landa Nanographic S10 X GAMUT ECG Print Implementation
2149 colors (14 Neon and Metallic colors removed)

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