Heidelberg upgrades colour control

The world's biggest offset press manufacturer, Heidelberg, is introducing what it says are extensive additions for its colour measurement and control systems, and for the Prinect colour workflow. 

It says the move is a response to the growing demands for efficient and dependable quality control in commercial, packaging, and label printing.

In Prinect Easy Control, Prinect Axis Control, Prinect Image Control, and Prinect Inpress Control, Heidelberg offers the market four spectral measurement systems for print shops of all sizes, and sheetfed offset presses of all performance classes.

The company says end-to-end spectral measurement, patented colour control, and a further enhanced Prinect colour workflow facilitate rapid, low-waste job changes, as well as quality monitoring and logging for production runs on all Speedmaster presses.

Colour control based on measured spectral values is the most promising method for achieving the desired colors as quickly as possible in commercial, label, and packaging printing, which is why Heidelberg has continuously developed spectral colour measurement technology.

“The consistent development of the entire Heidelberg spectral color measurement portfolio gives commercial and packaging print shops of all sizes the opportunity to optimise their colour workflow, moving it closer to the smart print shop model – even as far as autonomous printing,” explains Jürgen Mittmann, senior manager Product Management Sheetfed at Heidelberg.

Since it was first rolled out in 2010, Prinect Easy Control has been installed on 800 Speedmaster sheetfed offset presses. Now, Heidelberg has launched the next model of this successful measurement system onto the market. At its heart is a “high-quality” spectral measurement device that can simply be taken out of its mount and used for other purposes, such as calibrations in prepress.

The system can measure an A3 sheet in less than four seconds. An integrated video camera supports manual adjustment in line with the position of the quality control strip (lead edge, centre and rear edge of sheet). One new feature is that Prinect Easy Control can now also measure the small Dipco Micro print control strip (3.25 x 4mm measurement field). The measuring device is charged via induction when in its park position. Another new feature is the Netprofiler option for colorimetric calibration.

The measuring device is integrated into the Prinect Press Center 3/XL 3 control station technology and connected to the central colour database in Prinect Production Manager. Prinect Easy Control can take measurements under the standardised measuring conditions M1, M2, and M3.

Prinect Axis Control has had a similar overhaul. Working at a speed of 200 mm per second, Heidelberg says it is the fastest measuring system in its class, and says it is equally suitable for applications in commercial and packaging printing. An autofocus function automatically compensates for different substrate thicknesses during the contactless measurement process.

One new development is that Axis Control now supports measuring condition M1 (taking into account optical brighteners in the paper). The device automatically detects the quality control strip on the print sheet and the paper white. Thanks to its tracking feature, Prinect Axis Control supports a precise measurement process even when the print sheet is not straight.

The new-generation Prinect Image Control 4 measures both the quality control strip and the entire print image. This measurement system is particularly suitable for label and packaging printing, when colour management needs to be absolutely identical for numerous repeats spread over the sheet. Solid areas, screened images, and Mini Spots are all measured just the same for color control and quality evaluation purposes. Prinect Image Control is available with the options of image error recognition and PDF inspection, which are carried out during a one-time scan of the sheet.

The patented opaque white control system from Heidelberg is integrated as standard. The single measurement head now also supports measuring condition M1. Another standard feature enables users to transfer data to the Prinect Color Toolbox in Prinect Production Manager or to third-party software solutions. Up to four presses can be connected to Prinect Image Control. Prinect Image Control 4 is operated centrally, from a 24-inch multi-touchscreen.

According to Heidelberg the spectral inline color measurement system Prinect Inpress Control for Speedmaster presses in the Peak Performance Class ensures that setup processes can be completed fast with minimal waste and consistent, stable colour management. Inpress Control adjusts colour management and register on the fly and in the space of just a few print sheets. Once the tolerance values stored in Quality Assist have been met, the production run itself starts automatically.

Prinect Inpress Control 3 is now able to measure and control opaque white on dark, metallic, and transparent substrates. This expands the range of applications in packaging and label printing enormously.

“Measuring and controlling colours on opaque white is the state of the art. However, there has not previously been a solution for controlling opaque white itself – until Heidelberg made that possible for the first time with Prinect Image Control. In the future, we will be able to offer this patented control algorithm for inline control with Prinect Inpress Control 3, too,” explains Mittmann. The new function is to be integrated as standard into the measurement and control system by the end of 2022 and will be unveiled for the first time at the end of April, during Label Days at the Print Media Center in Wiesloch.

Another new function designed for label and packaging printers working with expensive substrates is automated waste detection when setting up with Prinect Inpress Control 3. Thanks to this new waste detection feature, waste sheets can be used to set up the inking units. A sensor in the feeder detects printed waste sheets and automatically activates Inpress Control so that measurements are only taken on freshly printed sheets. The system has been installed in a Speedmaster XL 106 for label printing for the first time, and its performance to date indicates the customer will be able to reduce setup-related paper costs by approximately 80,000 Euro per year.

The new version of Prinect Inpress Control 3 allows users to save paper white values for the substrates stored in the paper database. If substrates are transferred to the Speedmaster along with their paper white values, setup takes less time because the current substrate won’t need to be measured with the hand-held measuring device at the start of the job. It is another step that supports the Push to Stop philosophy.

A central colour database in Prinect Production Manager takes colour values that have been saved on one press and makes them immediately available to all other presses in the same network. This eliminates the need for multiple measurements and ensures all press operators and presses are working to the same specifications.

A single interface is available as standard for importing and exporting CxF data (colour exchange format – the spectral data for spot colours). This means that ink settings can be read from, or transferred to, third-party systems. The values of Pantone, HKS, Fogra 51, and Fogra 52 are also stored in the database. In addition, the stored colour values factor in potential shifts in the colour coordinates during the drying process. On that basis, the corresponding wet values for an ink on a specific paper are stored in the database.

Heidelberg has also expanded the API interface of the Prinect Production Manager so that spectral measured values from Prinect colour measurement systems can also be transferred to third-party software products for the purpose of quality analyses.

When an order is started on a Speedmaster press, the optimum colour presettings and pre-inking are set in line with the ink name. This helps to prevent considerable overinking at the start of printing, which saves paper and ensures the production run can get underway faster.

Color Assistant Pro adapts the substrate-specific characteristic curves with the aim of achieving a stable process. To do that, an algorithm controlled by artificial intelligence runs in the background to monitor colour management and the setting of the ink zones. It checks the extent to which the settings can be improved. This culminates in a continuous process of optimisation and adaptation to new printing conditions.

Color Assistant Pro is supported by Prinect Easy Control and Axis Control. In particular, says Heidelberg, it realises its full potential when combined with Prinect Inpress Control 3, which continuously measures inking during the printing process. Thanks to a self-learning process, operator error caused by a lack of adequate training can be avoided and the colour presettings are optimised automatically.