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FLEXO Magazine : July 2010
Technologies & Techniques approaching the design in a flat, 2D approach is insufficient. For the designer who needs to consider artwork distortion, there is the real potential of damaging brand integrity if the process is not handled correctly. Most packaging designers have trouble with the distor- tion of shrink sleeves. It takes shrink tests, guesswork and headaches to get everything positioned and compensated accurately. Artwork designers struggle to express ideas for a curved surface on a flat canvas. And after all is said and done, the packaging often never looks quite right. Graphics that fall in moderate/high shrink areas will become distorted on the finished product. Barcodes can be a real challenge. If distorted, they cannot be scanned consis- tently. The color and transparency of the packaging can also be altered because the hue and density of screened areas can shift in areas of extreme shrinking. Matching graphics across the seam of the sleeve where a 360 degree view is desired is also problematic. If all of this was not enough, different materials shrink dif- ferently—even differently between the vertical and horizontal directions. The result can be ambiguous artwork that leaves prepress professionals guessing about the designer’s intent. The process is complex and labor intensive, involving a number of trial and error steps to get the design right, resulting in the words brand owners hate to hear: longer lead times—as much as six months. The Process Conceptually, the shrink sleeve process for products, stretch sleeves or multi-packs is simple. Artwork is designed that will look correct when shrunk. After it is printed, a seam is made to create the physical sleeve. The sleeve is placed over the product and then shrunk by heat. It’s not quite that easy. Distortion that occurs during shrinking has to be taken into account during the design and prepress stages. The “predict- ed” distortion is calculated according to the contours of the bottle shape. The printing of text and graphics on the label is pre-distorted, so that after shrinking the finished result looks exactly as if it were printed directly onto the container. Traditionally for the designer, there have been a few ways to plan for distortion. The easiest way is to avoid it completely by creating distortion-friendly designs, where essential art- work elements are in areas of little or no shrink. Of course, the most tedious way is to manually proportionally scale artwork elements. Typically, designers follow three manual workflow steps in shrink sleeve packaging: 1. Predict the behavior of the shrink sleeve production process and digitize the distortion that is produced 2. Based on this prediction, show the artwork distortion on the sleeve 3. Pre-distort the artwork to compensate for production It is still not unusual to find some designers photocopy- ing grids onto a plastic, wrapping it around the container, ‘se aming’ it with a few pieces of tape, and using a hair dryer to shrink the material. From there, by measuring the effect of heat on the grid, a designer can try to estimate the shrinking effect in a design. There are other, but until recently rarely used, options. With the aid of warping software, designers can fully distort the artwork file. These solutions work on a silhouette curve (round When finished, the software can export a 3D model to visually verify that the warped graphics will be acceptable. www.flexography.org july 2010 FLeXO 37 FLXO_July10_v2.indd 37 7/16/10 9:36 AM
Sustainable Summer 2010