Expanded Gamut Printing (ECG) has been a transformative concept in the printing industry for decades. The fundamental principle of ECG is the creation of printed colors by overlapping two or more core colors from the spectrum of yellow (Y), magenta (M), cyan (C), black (K), orange (O), green (G), and violet (V) or blue.

Though often seen as a recent innovation, ECG’s roots stretch back over 25 years, evolving alongside printing technology.

The concept of expanded gamut printing first gained attention in the 1990s when printers began overlaying yellow with magenta to create vibrant reds for promotional flashes in print designs. By 2007, the introduction of Hexachrome colors brought ECG into more printing discussions, highlighting its potential for cost savings, reduced wash-ups, and enhanced color options. Despite these advantages, ECG has yet to become the standard flexo printing process. Why?

Challenges in standardizing ECG for flexo printing

While ECG offers clear benefits, its adoption has been slow due to technical challenges. These are primarily related to consistency and predictability. Color builds in ECG rely on theoretical mathematical models that assume perfect printing conditions. However, real-world variability in plate resolution, ink viscosity, and anilox technology has made widespread implementation difficult.

Historical technical barriers to ECG adoption

Plate Screen Resolution Limitations

In the 1990s, the maximum plate screen resolution was 100 LPI (lines per inch). This was insufficient for ECG, as the human eye could see the dots in the color builds, leading to dull and inconsistent colors. The ideal resolution for ECG printing is 175 LPI, a standard that is now widely used in both wide web and label printing, making ECG more viable today.

Ink viscosity and flow control

Consistent ink viscosity is crucial for maintaining predictable color reproduction in ECG. Early printing presses lacked the necessary controls for ink viscosity, temperature, and flow rates. Modern flexographic presses have significantly improved in these areas, ensuring better ink stability and reducing color variability.

Evolution of anilox engraving technology

Anilox rollers and sleeves play a critical role in ink transfer consistency. Over the years, engraving technology has advanced from 800 LPI to finer engravings—up to 1400 LPI today. However, while finer engravings improve print resolution, challenges remain in controlling ink transfer due to changes in cell shape, wall thickness, and volume capacity.

For example, an 800 LPI anilox roller has a 25-micron cell opening with a 7-micron wall, whereas a 1400 LPI roller has an 11-micron opening with the same 7-micron wall. Such changes impact ink transfer efficiency and cleaning frequency of the anilox, influencing ECG reliability.

Apex International’s GTT 2.0: An ECG enabler

Apex International has addressed many of the challenges associated with traditional anilox technology through its GTT 2.0 engraving. This technology provides enhanced ink transfer consistency and volume control, making ECG printing more predictable and efficient.

Why ECG is essential for the future of flexo printing

With advancements in technology, ECG is now more practical and cost-effective than ever. The benefits include: cost savings, increased press efficiency, enhanced print quality, and sustainability.

This article originally appeared here on the Apex International website.