Global Graphics Software has developed Advanced Inkjet Screens (AIS), a set of new software screens that add the ‘final polish’ to output produced on inkjet presses.
AIS has been designed to smooth out imperfections caused by the physics of jetting ink onto a substrate. Two versions are available: Pearl produces an effect described as ‘very natural’ on more or less absorbent substrates; Mirror is intended for non-absorbent and poorly-wetting surfaces such as tin cans and flexible packaging, and also areas of dense metallic ink.
On fairly absorbent and/or wettable substrates, drops tend to coalesce along the substrate surface, causing visible streaking. This is especially the case in mid- and three-quarter tones. Pearl is an advanced dispersed (FM) screen, optimized for natural images on a more or less absorbent substrate. It is targeted especially at addressing chaining and streaking artefacts.
On non-absorbent, poorly wettable substrates, prints are characterized by a mottle effect that looks like orange peel. The problem appears to be triggered by ink shrinkage during the cure and is especially noticeable in areas with reasonably high total area coverage. Mirror is designed with a microstructure targeted at countering the mottling, or ‘orange peel’ effect, that can be seen when solid colors are used on non-absorbent or poorly-wetting substrates.
The software screens can be applied to any print industry workflow. They can be added to presses already on the market, or incorporated into an inkjet press that’s still in development.
Global Graphics Software stated that AIS will improve print quality ‘out of the box’ on many inkjet presses, making them quicker to deploy. AIS screens can be applied on the back of any RIP that allows access to unscreened raster data. Alternatively, they can be applied during rendering in the Harlequin Host Renderer RIP.
Tom Mooney, product manager at Global Graphics Software, said: ‘Most printing software assumes that a press can print a perfect grid of dots. In practice, on an inkjet press there are often variables that lead to changes in the size, shape or position of each drop. Even though these individual drops are very small, the result is that they coalesce, creating artefacts and errors that are often visible at the intended viewing distance in the finished print.
‘By measuring the characteristics of the drop generation and interaction with the substrate, it is possible to fine-tune the halftone dot shapes and placement within the screening definition to mitigate unwanted variables. The result is print that is visually largely error-free, because the optimized screen compensates for and masks the effect of errors in the print process.’
Mooney added: ‘They are particularly effective where inkjet output will be sold as part of a brand’s marketing, such as packaging, where AIS allows converters and label printers wanting to use cheaper stocks or the same stocks as for flexo, to produce sellable product.’