Screening Technology: Another Piece in the Puzzle

Today printers have many options to enhance flexographic print quality. Whether using flat-top dots, hybrid presses, or screening technologies there is a maze of information that must be navigated when choosing flexo enhancing technologies. With new flexo technologies, we are able to expand flexo and move jobs from competing technologies such as offset, gravure, and digital.
With advancements in flexo photopolymer plate and platemaking technologies such as MacDermid’s LUX ITP™ product portfolio and UV LED curing, comes the ability to hold finer highlight dots. These fine highlight dots enable designers more flexibility in creating art that will pop off the shelf and catch the eye of the consumer, especially with fade to zero effects. Surface screening has improved the everlasting issue with ink transfer and solid ink coverage helping those vibrant and saturated brand colors to become more consistent across packaging platforms.

Selecting, Curing, and Screening
Just as selecting the right plate and curing the plate are important, screening selection is a vital piece to implementing high-quality flexo. Screening selection will be dependent on your process and needs to be optimized for each process. One of the most important pieces of the flexo puzzle is optimization and control of the process. The evolution of screening selection, plate selection, and cure of the plate have made this piece more easily attainable.

Advancements in screening technologies are key factors in the improvement of flexographic print quality. These screening technologies combined with plate technologies and cure technologies have opened the door to two major players in the screening world: highlight dots and surface screening. Screening is the translation from the continuous tone image to the printable image comprised of dots of various shapes and sizes. How we screen an image ultimately determines how faithfully that image is reproduced and how much of the original contrast, saturation, and detail is preserved. Screening and new screening technologies are at the heart of flexo platemaking today.
The top three screening advancements are Esko’s Crystal, Hamillroad’s Bellissima, and Thermoflexx’s Woodpecker Nano. This article will focus on these screening technologies. Join us as we look at:
  • What they do
  • How they work
  • How to maximize their use

Thermodflexx’s Woodpecker Nano
Thermoflexx recently introduced a new surface screening technology, Woodpecker Nano, for its flexo plate imagers which offers higher solid ink density and smoother laydown. This new technology also eradicates dot bridging and tonal jumps minimizing and eliminating halo effect in solid types and trailing edge or void effect. Ink savings are an addtional benefit in using this technology due to more efficient ink pick up and transfer from low volume anilox rollers allowing for lower pigmented inks.

Woodpecker Nano utilizes the high-resolution Thermoflexx optic usually used to output 5080 dpi image files. Careful and accurate laser beam control allows repeatable and stable image implementation of these fine screens. It has been established that an input file resolution of 2000 dpi gives an optimum surface microstructure output for this optical path, already in place in most large format Thermoflexx imagers.

Woodpecker Surface Micro Structures are applied at the imager output avoiding the need for costly RIP options. Woodpecker Nano patterns are perfectly symmetrical and the finest available for LAMs layer digital flexo plates. Structures are applied to the highest line screen ruling (dots) with no need for protection or border. Nano screening is not object or subject-based and requires no decisions at the RIP stage.

Hamillroad’s Bellissima
Bellissima DMS is described as a transformative screening technology for flexo, rivaling the quality of print typically associated with offset and gravure. Bellissima DMS fuses the best characteristics of AM, FM, XM, GS, and CS screening while avoiding their limitations and problems.  The software delivers high-fidelity image reproduction while addressing highlights and fades. The solution’s lower dot gain translates to vivid detail and consistent color. It dramatically enhances the reproduction fidelity and color stability of flexo presswork.

On press, Bellissima helps overcome fundamental printing press problems inherent in the flexographic printing process including:
  • Reduced implementation time for screens and curves
  • Simplification of day-to-day repro tasks—reduced file retouching
  • Improved printed highlights and overall tonal range
  • Cleaner printing on press leads to fewer pauses for plate cleaning
  • Reduced graininess in highlight areas due to smaller dots and more control over transition point

150 lpi AM Screening
Bellissima DMS

This screening technology is likened to producing high-definition versus standard images. Bellissima makes the best case for a stochastic screen for flexo. On the highlight end, each color has its own randomized pattern, so the dots don’t print on top of each other. The dots are smaller and they’re able to capture detail more effectively. This eliminates color shifts and reduces noise in flat tints.

MacDermid’s LUX plate technology has experienced excellent results with Bellissima screens. MacDermid’s LUX ITP 60 flat-top dot technology doesn’t require extra steps and sees exposure times down to 8-10 minutes. The plates are inherently less affected by oxygen than round-top dot plates, resulting in a smaller printed dot.

Esko’s Crystal Screening
Esko has different screening technologies to improve ink lay-down in solids for flexo. These techniques improve the density and opacity of the solid areas (the 100% tones) by adding texture on the surface of flexo plates. That way the ink holds better on the plate and transfers more uniformly on the substrate.

The latest screening technology from Esko is Crystal screens. Crystal comes in various versions, which can be tailored to each printer’s application, press configuration, and platemaking environment. Crystal screens require Esko’s XPS Crystal UV LED system (for more info about UV LED & Photopolymer Technology see our post on this subject). Crystal screening is based on WSI Screening and utilizes Esko’s boost technology. Crystal screens take advantage of flat-top dot plates to form smaller printable structures within the plate to further improve those benefits of cleaner vignettes and increased color gamut. This screening technology enables very clean printing screens without dot bridging, which improves plate and print consistency with dot uniformity and stability. 
Since producing custom screens and curves has traditionally been a manual and time-consuming process, Esko’s Print Control Wizard (PCW) has been developed to simplify this step for labels and flexible packaging. PCW simplifies the implementation of screens and curves for the flexo print process. The product quickly formulates data sets for screens and curves, creates print targets (mid-tone targets and highlight targets), maintains a Dot Gain Chart, and allows for the entry of various parameters like what plates are being used, thickness, ink set, anilox properties, and so on. The software is a non-technical wizard-based tool which according to flexo printers, “Dots just print cleaner and plates come up to color faster.”

When to Use Screening
The answer to this question depends on what markets you are in and what markets you want to be in.
Ask yourself:

  • What competitive forces are you facing?
  • How much ink transfer am I looking for? What value?
  • Am I looking to expand my tonal range? What screen ruling?
  • Is fade too zero important for me?
In summary, know your market. Adopting a technology doesn’t necessarily guarantee you market share but it does establish a base for you to provide options to your existing or potential client from which you can grow or at a minimum protect your existing market.

To learn more about screening technology and photopolymer plates email us today email us today.

Written By: Tony Dalleore, General Manager – MGS Australia

Tony Dalleore, General Manager of MacDermid Graphics Solutions – Australia, has been a valued MacDermid employee since 1999. Tony is an expert in both liquid and sheet photopolymer solutions. His dedication to MacDermid and expanding flexo in Australia and the Asia Pacific region has helped us become a leader in the market and region.

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