ImagesMagUK_Digital-Edition_Nov17

Manual application makes it all but impossible for an operator to uniformly cover the area with pretreatment and there’s likely to be even less consistency from operator to operator. Often, the solution will be applied too thickly in the centre of the designated image area and too thinly at the edges. While it would be tempting to compensate by applying a thicker layer all over, this can result in major printing issues and it’s hardly cost effective to use any more pretreatment solution than is absolutely necessary. You also have to factor in the further waste from inadvertent spraying of pretreatment outside the image area. In addition, the inconsistent application of pretreatment solution makes it harder to troubleshoot printing problems. If some images in the same print run come out looking better than others – or don’t last through as many wash cycles as others – it’s impossible to tell if pretreatment is the issue if there’s no consistency in its application. High quality automated pretreatment equipment solves these problems by allowing operators to dial in a precise amount of solution, apply it evenly and consistently, and confine the treatment zone to only the area where it’s needed. And by keeping close tabs on the settings used for each print run, operators will have the information necessary to fine tune the amount of solution necessary to achieve optimal results. Automated pretreatment systems also limit the amount of chemical spray the operator – and anyone else in the area – is exposed to, and reduce the time and expense involved in cleaning up overspray from adjacent surfaces. Both pretreatment options – manual and automatic – should be followed by heat curing prior to digital printing. Times vary based on ink and fabric types, but 30 seconds under a heat press is a good starting point. In some cases, the operator can position (hover) the heating element over the substrate to drive off some of the liquid prior to pressing the substrate. In order to minimise time spent on trial-and- error testing, operators should keep detailed records of what works best on various ink/substrate combinations. Despite the benefits inherent in automatic pretreatment, I wouldn’t want to discourage people from getting into DTG printing simply because they can’t afford an automatic pretreatment system. While there is no way manually-applied pretreatment can compete with automatic pretreatment application, acceptable – if not exceptional – results can be achieved. But I would always recommend investing in a high- quality automated pretreatment system just as soon as your business’s finances allow. www.mrprint.com

(Left) A print on a pretreated shirt. (Right) The same print on an untreated shirt

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