In Parts 1 and 2 of this three-part series, we talked about how the three main variables in heat pressing are temperature, time and pressure. We then went on to look at what to look for in a heat press to ensure you meet these conditions consistently.FULL STORY
Digital Decorating: Heat Transfer
Plastisol Heat Transfers: The New Decorating Standard for Hats?
In the decorated apparel industry, one of the ever-present challenges of our business is choosing the proper method for applying the desired design to our products.
In my case, the choice of the ideal printing method to use for our hats is not one that I can make lightly, or apply broadly to each of my company’s products. In recent years, the emergence of high-quality heat transferring techniques, particularly plastisol transfers, has made this key decision even more complex.
There was a time when screen printing was far and away the most widely used printing method for most designs. Now, while most industry experts still agree screen printing produces the most durable and attractive results, modern heat transfer techniques can create images that rival traditional screen printing methods in both appearance and durability.
Are heat transfers the new go-to solution? As with so many things in business, there is no simple answer, but here are a few key points to consider about how heat transfers compare to traditional screen printing techniques, especially on headwear.
The essential elements of modern screen printing have been around since the early 1900s, when the development of screen emulsions and photo-reactive stencils allowed for the creation of much more detailed screens.
While technological advancements have streamlined the process and made the resulting prints more precise and detailed, the basic method of applying ink through a fine-mesh screen remains the backbone of the technique with which most artists and printers today are well acquainted.
While the details of the screen-preparation process and ink application may differ depending on the product to be printed and design being applied, ink is essentially forced through unmasked sections of a mesh screen and applied to the item below. The ink is then cured by any number of drying methods and the process is repeated for additional colors, if needed.
Plastisol Heat Transfers
Heat transfers have been used for years as a reliable alternative to costly and complex screen printing methods. Graphics are printed onto special transfer paper and then applied — using heat and pressure — to the desired garment.
More recently, the development of plastisol (a suspension of PVC particles that flows very much like ink) has paved the way for a new method of creating heat transfers that incorporates screen printing techniques. Plastisol transfers are made by screen printing designs using plastisol ink onto special transfer paper. A heat-activated adhesive is then applied to aid in adhering the transfer to the garment, and then a heat press is used to apply it. The resulting graphics have much of the detail and precision of a screen printed image.
There are several distinct types of plastisol transfer applications. In each case, the design is applied to the garment using a heat press. The transfer backing paper is then peeled off in one of three ways:
1. Cold Peel: Once the design is applied, the garment is allowed to cool before the transfer paper is peeled off. The finished image generally is left with a glossier appearance.
2. Hot Peel: As the name implies, the transfer paper is removed from the design immediately after pressing. Doing so leaves a less-glossy final image with more of a matte finish.
3. Hot Split: In hot split applications, the plastisol transfer is applied without a bonding adhesive, instead relying on special inks in the transfer to melt into the fabric to create a lasting bond. The paper is again removed while the design is still hot, in this case taking with it some of the ink, leaving the design with a softer feel and brushed matte finish.
Plastisol Heat Transfer Advantages
Unlike traditional heat transfers, which often are printed using consumer inkjet printers, plastisol transfers are made using screen printing techniques. As such, they must be ordered from, and created by, companies with the proper equipment and expertise. However, once on hand, plastisol heat transfers offer a number of valuable advantages.
Design flexibility is key to success in this industry. One of the primary downsides to traditional screen printing, particularly on hats, is the number of colors that can be effectively used in a given design. Reliable screen printing on headwear is limited to a maximum of two colors and does not allow for color gradients, since the screen printing application process allows for colors to either be present or absent.
Plastisol heat transfers, on the other hand, can be created using up to eight colors and integrated into the design in ways traditional direct screen printing cannot achieve. This selection of color options allows for photographic images to be used in designs, with the resulting transfers often difficult to distinguish from screen printed graphics.
The inherent complexity of screen printing also makes heat transfers such an appealing alternative. For each screen printed design, screens must first be coated with emulsion and allowed to dry. Films are then created for each of the desired elements in a given design. The films are then used to expose, or “burn,” the design into screens corresponding to each required color. Once the screens are complete, the product to be printed must then be properly aligned with the screen, and only then can ink be applied. It must then be set using a drying tunnel or another method. If additional colors are required, the process must then be repeated, necessitating screens being changed. This is part of what makes screen printing a notoriously lengthy procedure.
Additional colors also lead to potential registration problems, whereby one color is not properly aligned with the previous color. This complex process makes small-order runs impractical, as creating unique screens for only a few prints is not cost effective.
In heat transfer printing, all you need is the proper heat press once the transfers have been created. While high-quality heat presses can be expensive, the proliferation of heat transfer printing has created a large second-hand market for presses, often enabling start-up companies or individuals to acquire heat presses at significantly reduced prices.
Because transfers can be ordered in quantities as low as eight to 10, even small runs can be created cost effectively, with no screens to create, emulsion to mix or ink to wrangle. While we may use screen printing on larger quantity projects, heat transfers are a much more practical option for smaller custom orders or for businesses with lower volume needs.
I’ve found that top-quality heat transfers created by professional manufacturers often are very difficult to distinguish from screen printing to the untrained eye. However, to ensure the best results, it’s important to know that different materials require different pressures and heat times. The color onto which you’re printing will also affect the quality of the resulting image, so careful planning and consideration should be used about the type or order to be fulfilled before ordering transfers.
With all of the above in mind, I’ve found that plastisol heat transfers are generally much more cost effective for smaller runs that require multiple colors, as screen changes and creation add a significant burden of both time and resources. The simplicity and low overhead of heat transfers also make them a much more practical option for individuals or businesses looking to enter the custom printing industry.
However, screen printing will continue to be a valuable tool due to its slight edge in quality and appearance when printing larger orders that contain fewer colors. In addition, because each client’s need is unique — and due to distinct differences in look and feel between each process — both screen printing and heat transfers will continue to have their place in any successful, full-service custom printing operation.
Brian Burr is chief operating officer of wholesalehats.com in Palm Desert, Calif., which has produced embroidered garments for clientele that includes Google, NASA, MTV and the United States Army. Brian has been involved in every aspect of the embroidery industry for more than 18 years, and has extensive knowledge of embroidery equipment, techniques and the business of custom printing and embroidery. For more information or to comment on this article, email Brian at firstname.lastname@example.org.
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