By mastering the ever-expanding range of special effects that can be achieved on apparel today, you can take your relationship with clients to an entirely new level.
By Lon Winters
Remember that the combined thickness of the mesh and stencil is directly related to ink deposit. If we want a softer, smoother, or thinner print, we use a higher mesh count with a thinner stencil. Conversely, achieving prints with more texture or thicker ink deposits will require a lower mesh count with a thicker stencil. Because we often want a very thick ink deposit with some of these applications, we modify our typical coating techniques a bit for the very low mesh counts and specialty emulsions and capillary films that are involved. Capillary film is available in thicknesses ranging from 20 microns all the way up to 1000 microns; we usually stay in the range of 100 to 400 microns for best results in specialty applications. Even with extreme HD effects, it can be easier to stack two or three sheets of capillary films together rather than trying to get full release from a 1000-micron film. Most thicker films use pure photopolymer sensitizers to allow for faster screen exposures. Developing and washing out the properly exposed stencil take a bit of “voodoo” as well to clear the finer details in the image.
Developments in ink technology and newer formulations introduced in recent years allow for a much broader range of effects than ever before, while making many of the more familiar products more forgiving in production. But there are some important printing considerations when printing these specialty products.
First, the planar relationships of the platens to the heads, squeegees and floodbars, and off-contact distance must be equal and consistent. This is particularly important for effects that require an exact ink deposit thickness. Many special-effect inks require a flash after printing if they cannot be printed last. They may require an additional cooldown station after the flash as well. In our shop, we may also choose to use a heated iron or roller with various papers to help get the textures we want at different stations within the print order. Sampling plays an important role in developing these specialty printing applications successfully. We do a lot of testing to determine the optimum placement of the special-effect screens, which in turn dictates where the flashes, cooldown stations, and on-press treatments will be.
Did you enjoy this article? Click here to subscribe to the magazine.