An Underbase With a Punch

CUSTOMERS AND RETAIL buyers always are on the lookout for that “something extra” in a printed garment that will set it apart from the average shirt. A great way of elevating prints above the competition without a lot of extra work is to get creative with the underbase print. Typically, an underbase print merely serves the purpose of blocking the garment color from affecting the ink colors that will be printed on top of it. But it can have an added function if you start to experiment with the possibilities.

In this column I will cover a modification to the underbase that gives an extra boost to the art that is printed on top of it. The expanding (or puff underbase) is a way of using the same artwork you might print in a standard method. Then, you can change the underbase print so, that upon curing, certain areas of the print will expand upward to create an exciting, dimensional look. The goal with this process is to keep it as a simple embellishment that will create added value to a screen print without destroying the integrity of the original artwork.

Figure 1. The boxing logo to be redesigned needed some extra dimension so that it had a higher perceived value. This artwork fit the mold for a design that would work with both an expanding and distressed underbase.

Finding the Right Artwork

The first step to any special-effects print is designing or picking the art around the specific qualities that a particular special effect has. It is essential to consider both the limitations and the advantages to an effect before the final art is decided upon. Otherwise, the artwork may have to be completely redone to work properly, or it will look cheaply executed.

For instance, the boxing logo that was presented to me for redesigning needed some extra dimension so that it had a higher perceived value (Figure 1). This artwork fit the mold for a design that would work with both an expanding and distressed underbase. The reason this artwork was ideal for these processes is that it had large, distinct areas of specific geometric shapes that could be modified underneath to produce a dimensional effect. These areas showcase the effect to the viewer because they are simple and obvious.

If I had picked a design that was created with many smaller pieces or was less bold with its graphics, the special effects wouldn’t be as clear to the viewer. From a profit standpoint it is a good idea for a special effect to justify itself. This adds value through a visible increase in the interest a printed graphic obtains for it to pan out in more sales. If the artwork helps the special effect show off, then it probably is a good choice.

Figure 2. A good test file will consist of a variety of shapes in different sizes and distances to print the file onto a scrap shirt to see how much it puffs up and how smooth the surface is.

The Expanding Underbase

The concept of this special effect is to create an image with real dimension that invites the viewer to feel the surface of the garment and see the image pop off the shirt in the right areas. This effect is achieved through the skillful use of modified ink that has a blowing agent added to the mix. A blowing agent is a compound that is added to ink that releases gas upon being heated. The result of gas forming inside the heating ink causes the ink to expand upward in a domelike shape.

Inks of this type commonly are referred to as puff inks, but I don’t recommend using standard puff ink out of the can for this process. The best results are achieved when you add a small amount of puff additive to an existing ink mix so it controls the amount of puff reaction. I normally look at the manufacturer’s specs on the puff additive and add between 5-10% so it doesn’t puff too much.

Another way to improve this process is to use a stretch additive to the ink. The stretch additive allows the ink to have a smoother surface than regular puff ink and maintains more detail of halftones or line work that is overprinted on top of the expanding underbase. I normally added 10-15% stretch to my ink for this method to help keep the detail from getting distorted too much.

White is the most common color for an expanding underbase ink. But there are some cases where a printer may want to use a color-expanding ink so it doesn’t lighten the overprinted colors too much. All puff ink underbases generally will lighten the overprinted colors on top of them to some degree. This can be dictated somewhat by controlling the amount the ink that expands and keeping the surface smoother. But the top colors will still change to a noticeable degree.

It isn’t necessarily a bad change and often will give the print a really cool, slightly worn-in look that is very popular. The downside comes if you are printing a bright red and don’t want it to turn pink or are trying to match a Pantone color. This can be very difficult because when the underneath ink puffs up it spreads out the pigments of the top ink and tends to lighten it noticeably. In this specific red example, it would be beneficial to use a red puff underneath for just the red areas in addition to a white puff to maintain the color purity of the top red hue (as long as you have enough flashes to do it).

Before you just throw a puff ink under your print and start the press running, it’s a good idea to test the ink and the process so you will know what the final results will be with the style of ink and art you’re using. A good test file (Figure 2) will consist of a variety of shapes in different sizes and distances from each other. Just print the file onto a scrap shirt to see how much it puffs up and how smooth the surface is.

A rule of thumb when using puff inks as underbases is to not have large solid areas and break up the underprint as much as possible. Otherwise, it will become to heavy and even could buckle the shirt fabric as the ink puffs up. In addition to the heavy feel, a large, puffed area on a shirt often will crack after several washes due to the nature of the puff ink as it bends over time inside the washer and being worn.

Figure 3. The point of redesigning the file in Photoshop was to create a metallic look.

Redesigning Art for the Process

I reviewed the test file, determined the best ink mix for the underbase, and proceeded to redesign the file to use this process in the best manner. The point of redesigning the file in Photoshop was to create a metallic look to the print that had dimension in the lettering, bolts, fist, and borders (Figure 3).

Something I discovered after using this process several times is that any large areas you underbase with puff should have significant color variation to them. A large, flat area of color that has a puff underbase shows the imperfections of the puff underbase loud and clear. The best result comes from using a couple of graduated fills or overlapping colors that help hide imperfections in the puff process with halftone dots.

The little bubble holes and bumps blend into the halftone patterns and don’t show nearly as much. As part of the test, you can experiment with a variety of specialty inks as well. Some metallic colors will work, and others won’t. This is due to the expansion of the suspended particles in the inks, and the ink may appear dull or mottled.

I had particularly good results using gold and silver gel inks, most likely because of their flexible gels they were suspending in. For the boxing print example, I wanted the final printed image to appear to have been welded to the shirt from the dimensional qualities of the puff ink working with the metallic silver gel.

Figure 4. I created the two underbase plates that create a controlled puff under parts of the print and leave other areas to appear flat.

Separating the Artwork for Expansion

I started separating the file for printing by creating a normal underbase and duplicating it. The next step was to look at the design carefully and decide where I wanted the special effect to puff up under the print to create the maximum visual and textural impact. I found a good way through trial and error to achieve a great look by using a two-color underbase.

The goal was to print the first underbase with normal ink and then print the puffed areas using the special mix kiss register with the first print and then flash the entire thing. In some cases, if the first under print (the non-puff ink) had a lot of halftones and graduations in it, I put in a flash before and after the puff ink as long as I still had enough flashes to finish the job. In this method, I created the two underbase plates that create a controlled puff under parts of the print and leave other areas to appear flat (Figure 4).

The rest of the colors were separated conventionally as if it was a normal print. I used a 180 mesh for the regular underbase and an 86 mesh for the puff ink screens. The top colors were printed on 230 mesh except for the metallic silver, which was printed through a 110 mesh.

Printing the Image

The final printing order was: Light gray, puff white, flash, dark gray, metallic silver gel, flash, black, and highlight white. A crucial consideration had to be addressed at the printing stage of this type of special effect — the flash dwell time. This effect would have failed on press and looked horrible if the flash cure caused the puff ink to expand on the press because the following colors wouldn’t have a smooth surface to sit upon.

The flash cure needs to be set to just gel the puff ink enough for other colors to be printed on top of it and not start the puffing process until the shirt runs through the dryer. This was checked during the testing process with the test print to ensure that the flash wasn’t too hot. I found it was better to flash slower and print less per hour than to wreck shirts and not know about it until they came out of the dryer and looked all rough and distorted. This happens because the ink puffed under the flash and then overprints, printing crooked and out of register on top of the raised ink.

The last concern in the printing process is the curing time. For puff underbases, it could take significantly longer in a dryer tunnel for the puff ink to fully activate. This is because the top colors tend to block some of the heat and gas that is released to build height in the ink. It takes around 45-60 seconds in the dryer for a maximum puff effect for this print. If the print is overcured, it might become brittle, lose washfastness, or melt back down and lose some of its height. So optimal time is determined to avoid these issues in the dryer.

Additional Strategies

This puff effect has a myriad of possibilities that are only limited by artists’ and printers’ imaginations. Some of the different ways that I have seen it used include simulated welds (as in the article example), simulated beads, feathers, belt buckles (printed to look like they were on the shirt), snakeskin patterns, fish scales, topographical maps, dog portraits, cartoons, sport ball textures (basketball, football, soccer balls), and many more.

The best way to start using this printing method is first to test it with some example ideas you can show people and sell it to a customer as an extra cost option. This way you will recoup the added time it takes to set up and the slower printing speeds that can eat into the profit margin.

I am a huge fan of creating and selling special effects rather than doing them as an afterthought and trying to deal with them on press at the last minute. This effect has a great customer response and really can be a best seller when someone runs his hand across the graphic and feels the image as well as sees it jumping off the shirt.