ScreenPro™ with PrintFlat™ technology from Global Graphics Software removes banding on large-format posters for Ellerhold Group – achieving 100% customer satisfaction and increasing the company’s market share of outdoor advertising products in digital printing.
Germany-based printing company Ellerhold Aktiengesellschaft wanted to enhance the printing quality of its large-format posters from its MLM_2600_NG digital printing machine, developed and built by its manufacturing subsidiary, Ellerhold Maschinenfabrik GmbH. Specifically, the printheads showed variation in printed density both between the heads and across each head, which produced clearly visible bands within some types of printed output.
Banding problem on sensitive jobs
- Ellerhold AG is the leading poster printing house in Germany with around 70% share of the premium billboard poster market
- Ellerhold prints all large-format posters with its MLM_2600_NG digital printer
- Ellerhold operates 6 MLM_2600_NG double side 2.5 m wide scanning head web systems for printing 200 x 252 dpi billboard displays.
Frank Ellerhold, founder of Ellerhold Aktiengesellschaft
“We had seen Global Graphics Software’s Martin Bailey introduce ScreenPro at The Inkjet Conference in Düsseldorf and believed this new technology might be the answer to this problem.”
Global Graphics Software’s Technical Services team worked with Ellerhold’s process engineer, Patrick Prezewowsky, to enhance the quality of the printed output using its award-winning technology, ScreenPro. A very fast and efficient multi-level screening engine that mitigates artifacts such as streaking and mottling from the inkjet print process, ScreenPro can be used in any print workflow, including Adobe®, Caldera, Esko, EFI and Sofha, with any combination of inks, substrates, printheads and electronics.
The team used ScreenPro’s PrintFlat technology to smooth out the banding present on Ellerhold’s large-format posters. PrintFlat corrects for density non-uniformity, which results in banding commonly caused by variation within a printhead or between printheads and is very time consuming to correct in hardware.
In ScreenPro every nozzle can be addressed separately on any head/electronics to achieve very fine granularity. PrintFlat adjusts the density within ScreenPro to produce uniform density across a print bar. The process can be automated for closed-loop correction and, unlike correction by adjustment of voltages, there is no effect on jetting stability or head lifetime, nor ink pressure and timing/drop speed variation.
The Technical Services team carried out tests, analysed the scanned prints and created a PrintFlat calibration workflow for the MLM_2600_NG designed to compensate for the non-uniformity in output across the print bar (poster width).
The team also used a variant of Global Graphics Software’s Advanced Inkjet Screens™ (AIS), available with ScreenPro and the Harlequin RIP®, which they adapted specially for scanning-head systems. These proved very effective.
Dr. Danny Hall, developer of the Advanced Inkjet Screens and Global Graphics Software’s chief screening scientist
“The project confirms that PrintFlat is a significant enabling technology, allowing the uniformity typical of analogue printing to be achieved routinely on a wide range of digital presses.”
Now Ellerhold’s process engineer uses Global Graphics Software’s online inkjet press calibration service, printflat.com, to upload the scans and automatically receive the correct calibrations so he can go ahead and print. The PrintFlat.com service is available to registered users who upload their PrintFlat scans and receive the calibrations they need to run their inkjet press at optimum quality.
ABOUT ELLERHOLD GROUP
Germany-based family business Ellerhold Aktiengesellschaft specialises in XXL Point of Sale display products, labels and packaging and is the market leader in printing posters for indoor and outdoor advertising.
Ellerhold Maschinenfabrik develops and manufactures special presses for multiple industrial applications.
With its headquarters in Radebeul near Dresden, Ellerhold has seven manufacturing sites in six locations in Germany, along with sales offices throughout Europe.