Images_Digital_Edition_January_2020

www.images-magazine.com 102 images JANUARY 2020 TIPS & TECHNIQUES We can virtually eliminate the need for registration Screen savers Computer-to-screen equipment is transforming the way in which screen printers work. Tony Palmer examines the different ways in which these labour-saving devices can benefit your print shop T he start of the process when printing any garment is the creation of a reliable stencil or screen to consistently pass the ink through. In the past this has been achieved by many different methods, but the basic process consists of coating a screen with light-sensitive emulsion and then creating a positive (‘shadow’) image on a sheet of film and then holding this film as close to the emulsion as possible while shining ultraviolet rays through it to expose (harden) the emulsion in the non-image areas. The film creation part of the process has changed over time. The early days of cameras, darkrooms and endless hours carefully cutting Rubylith film while setting curved text using a pencil line from a coffee cup outline and rub- off Letraset letters are well behind us now, as is the use of highly technical thermo-driven in-house imagesetters or outsourcing to expensive reprographics houses – the introduction of inkjet printers and polyester-coated carrier film has allowed most of us the freedom now to create positive films using a normal inkjet printer. But even the revolutionary move to inkjets has had some drawbacks: the film would stretch as the roll was used up, and the print heads would fail to work on a Monday morning no matter how many expletives were thrown in their direction. Moreover, the filing of used films was always a thing to behold in any print shop: after the press operator had glued the film to the platen and used it to mix three different colours on, and foreign bodies that were not of human origin had stuck themselves to the film forming a bond that was stronger than any man-made adhesive, only then would the film be filed... in the wrong job bag under the wrong customer name with the wrong date in the wrong drawer of on old filing cabinet that the sales department no longer used. Take it from me, you’ll never win back that time spent trawling through all the films printed over the past decade, only to find five films from a six-colour job filed under ‘G’ for ‘ginger guy that comes in the shop’. Once we have our precious positive film we need to position it onto the screen. This needs to be done with precision as it is imperative that all screens are made in at least a similar area to each other – crosses, tick marks, crosshairs and registration marks are all important in image placement. This is a common failure point as consistency is passed to the guy who didn’t get home until 7.30am and looks like he needs a bucket of Red Bull just to function. And so we enter the next generation of screen imaging: modern computer-to- screen (CTS) systems all use ‘electronic films’ in the form of data files that are automatically named, can be searched and are stored on a drive the size of a packet of tissues. (They still get stored under ‘D’ for ‘Dave’s-final-new-final- revised-approved-final.tif’ but we know exactly what we mean.) M&R’s i-Image S CTS sy stem Before CTS simplified the filing system, films were stored in homemade cardboard folders