The Do's & Dont's of Special-Effect Inks
Davis points out what ink combinations and procedures will and worn't work for special-effects applications.
As garment screen printers across the land attempt to come up with new printing methods and effects to dazzle the consumer, many are applying unique processing techniques to specialty-ink products that are already on the market. Just as with garment-graphic designs themselves, the range of modifications and techniques that can be applied to special-effect inks are as vast as the imagination. As more and more printers start "thinking outside the box" in their use of these inks, special-effect prints are resulting that the ink manufacturers themselves never dreamed of.
High-density clears, metallics, reflectives, and crystalline inks are now being mixed, modified, and overprinted to create new twists on old ideas. As these new concepts and procedures surface, they typically offer new challenges, often in both the inkroom and on press. This month, we'll explore some of the do's and don'ts to keep in mind when applying unconventional production methods to these unconventional special-effect inks:
Don't use too many special-effect inks on one print
In most cases, the limit on the number of special-effect inks you want on any one garment is two. If printing on a dark garment that requires an underbase, you will already need two flash units in order to flash the underbase and one of the two special-effect inks. However, the majority of printing presses in the US do not support more than two flash units.
To build more than two special-effect inks into any one graphic would mean either sacrificing the quality of one special-effect ink by having to overprint that ink while it's still wet or adding an additional (third) flash unit to the press--which might mean sacrificing another color. This represents a great deal more trouble, time, and cost than the third special-effect ink is worth--in most cases, consumers won't even notice more than two special-effect inks in a single design.
Do engineer graphics so that metallics or glitters print last in the sequence
Due to their reflective nature, these inks are very slow to cure and resistant to the flashing process. This means their use can slow down the entire production process if they need to be flashed on press. Printing them last means that all curing can take place in the dryer.
The one exception to this rule is when a design calls for a high-density ink, which must be printed last and necessitates flashing of the metallics before they are overprinted. See the next section to learn more about high-density inks.
Do always print high-density as the last special-effect ink in any printing sequence
This guideline bears consideration for several reasons. First, you would not want to depress a high-density print with subsequent print since it could adversely affect the overall height of the high-density ink film. Additionally, overprinting would mean that the high-density ink needs to be flashed. Finally, after flashing, a high-density ink film provides an inconsistent printing surface, which could adversely affect the continuity of any subsequent ink printed over it.
Do engineer prints so that multicolor puff effects are achieved with a single white-puff underbase
In other words, don't attempt to print excessive numbers of puff-ink colors. Instead, overprint the white-puff underbase with the conventional plastisol colors that the design calls for.
Although you can stagger your mesh counts when printing multiple puff colors, the required flashing will cause you to sacrifice resolution and overall height of the puff effects. I have seen instances where printers have tried to print four, five, or six individual puff colors and ruined the overall appearance of the design because the colors wouldn't flash properly.
Don't attempt to produce fine details when printing with most special-effect inks
Due to the courser mesh counts that most special-effect inks require, producing fine details is typically impossible. If the required detail is too great on a puff print, you will sacrifice the puff height for detail. On inks such as metallics, glitters, or reflectives, excessive detail will restrict passage through the stencil of larger special-effect ink particles, which can result in clogged screens.
Don't print large image areas with high-density or puff inks
The total height of the ink film in both puff and high-density printing applications is determined by a combination of the mesh and stencil thickness. The center of large image areas (open mesh areas) get no support from the stencil. This can result in a slightly concave ink deposit as the deposit thickness will be greater near the edges of the open area than the center. This concave profile will prevent you from achieving the desired high-density or puff effect.
Don't print expensive special-effect inks simply for the sake of printing expensive inks
Although inks like reflectives add excellent value to your printed garments, their expense can take the final product cost beyond a reasonable level for the consumer market. In many cases, a customer wanting the flash of reflective ink may be just as happy with a less-expensive metallic ink and save dollars to boot.
From the retail standpoint, most consumers would never even notice a reflective ink hanging on the rack in a store unless they just happened to catch the garment at the right angle relative to a light source. Metallic inks, on the other hand, scream from the garment and are far more eye catching at retail settings. This is not to deter anyone from using reflective inks, which are especially suited to garments that will be worn in dark areas that are lit by man-made sources; however, cost needs to be considered before going to production.
Do conduct extensive testing on new special-effect inks to ensure that you can achieve the desired effect
Gel printing, for example, is designed to provide effects ranging from high-gloss finishes on regular flat inks to a thick, rounded lensing effects on conventional prints. Without a thorough understanding of the printing parameters and capabilities of these inks, the end results can often be much less impressive than expected.
Do experiment with different product combinations and procedures for printing special effects
New special-effect ideas should be tested in the inkroom first. Some methods you can apply to expand the range of results you get from special-effect inks include the following:
* extend a silver glitter ink to achieve a silver crystalline ink for overprinting.
* tint silver metallics with toners or pigment concentrates to achieve colored metallics.
* add metallic or glitter inks to a clear gel to achieve metallic gel effects.
* add fluorescent materials to gel inks to achieve fluorescent gel effects.
* overprint metallics or glitters with a transparent color to achieve a different-colored metallic or glitter effect.
The possible combinations of specialty inks that you can explore are quite numerous. However, you will face some limitations. For example, you should not add a metallic ink to a puff. The inherent opaqueness of puff inks makes adding a product, such as a metallic ink, impractical. You will not see the metallic ink as it would be suspended within the ink film.
As with so many other aspects of textile screen printing, the key is to experiment and test new ink-usage ideas often. Your options are only limited by the capabilities of your printing process. The more time you invest into R&D for specialty-ink applications, the more you'll know the limitations of your process and the inks you use.