A partnership with French colour management specialist Alwan is delivering automated plate curve adjustment for QuadTech press control systems users.

The deal with Lyon-based Alwan Color Expertise teams QuadTech’s Color Control System with SpectralCam with Alwan’s Print Standardizer software to compensate for dot gain deviations and also confirm compliance with ISO 12647 and G7.

Measurement data from the QuadTech system is converted to L*a*b* and densitometric values, including  dot gain or tonal value increase. This information is then analysed by the Alwan software to determine dot gain variations and generate dot gain compensation curves, per job or over a specified time period.

The Alwan system also monitors and stores data from multiple presses or different paper stocks used on a press. The companies say the combined solution can easily be integrated into an existing workflow.

Alwan president Elie Khoury says many factors can lead to dot gain variations: “These include paper, ink set, damping solution, room conditions – such as temperature and humidity – printed forme content, and the mechanical properties of the press. “Maintaining constant control over dot gain is essential because increases of even three percent can result in colour changes detectable by the human eye.”

He says commercial printers will be able to achieve the same quality from their web-fed and sheetfed presses. “With the new automated inline measurement and standardising technology, web printers can achieve print consistency and dramatically decrease make-ready time,” he says.

QuadTech product manager Greg Wuenstel says monitoring and optimising dot gain compensation curves has traditionally been a labour-intensive task because of the diversity of substrates, “not to mention the many factors that can cause deviation”.

Combining the technologies will provide a fast, reliable means of ensuring consistent, ISO-compliant quality in web-offset.

Khoury founded Alwan in 1997 with an emphasis on standardising and controlling colour throughout every stage of production, and has led to it become a world leader in the field.

Picture: Dynamic press calibration curves are generated by the Alwan software to be applied on the CTP device