Ask five different people what a heat transfer is, and you’ll likely get five different responses. And, if you visit THE NBM SHOW to learn more about heat transfers, you will encounter a dozen different products that may seem similar but are really quite different below the surface. In reality, ‘heat transfer’ has become sort of a catchall phrase to describe almost any process that relies on heat to apply some form of graphic decoration to a product.
For those who have been in the industry for a while, the term heat transfer typically conjures visions of a heavy plastic film affixed to a garment. So-called ‘old school transfers’ typically had a rubbery feel and a shiny surface, and usually didn’t survive too many trips through the laundry before cracking and peeling. It was considered a cheap alternative to screen printing and was quite popular in souvenir T-shirt shops where the customer chose a blank shirt, and then picked out a graphic from an assortment of stock transfers.
But that was then. Now, heat transfers have radically improved, while at the same time giving way to new formats and processes. Though many versions now exist, when taken as a whole, transfers typically fall into one of two categories—materials or ink.
Material-Based Heat Transfers
In their original form, heat applied graphics were confined to vinyl, fabric and twill letters, and numbers with heat-activated adhesive backing. Thus, they can be described as some type of physical material or film that gets permanently affixed to a surface through the use of heat and pressure (heat press). Typical applications include athletic uniforms, sports jerseys, and sorority/fraternity wear. But, transfers can also be applied to non-apparel surfaces such as signs and wall panels, which opens up the range of products available for decoration.
Many of the early transfers were created using rigid materials, which sometimes caused issues when applied to apparel, as the transfer would not stretch with the garment during normal use and/or laundering. The end result is that they would begin to peel off over time. With new advances to material technology stretch materials are now being offered for use with stretch garments.
With most material-based heat transfers, business owners can either contract out the production of the design on the material and heat apply it in-house, or create the transfer themselves.
Producing material-based heat transfers in-house is fairly simple. It requires three basic pieces of equipment in addition to the media—software, a cutter, and a heat press. The process is generally quick and easy, and the cost of the equipment is very reasonable.
For simple one-piece applications, such as a single number, the design is created using software designed for use with a cutter (vector-based). The material is loaded into the cutter and the desired item is cut from the material. It’s then affixed with the heat press.
In the case of multi-piece applications, such as a player’s name in an arc, the individual letters must be cut out, but held in place in order to assure proper alignment. Some heat transfer products such as vinyl, have two layers – the vinyl material and a clear carrier sheet. After cutting, you can easily peel away the vinyl that does not belong (often called “weeding”), leaving only your image on the clear sheet.
Note that rhinestones also fall into this category. In most cases, the rhinestones themselves have adhesive backing. Design layouts are created and then secured using carrier sheets. The rhinestone design is pressed and the carrier sheet is removed. An oversimplification of the process, but in reality it is a fairly simple technique that fits into the category of material-based heat transfers.
Another form of material-based heat transfer is the print-cut transfer, also referred to as an opaque transfer. In this case, an image is printed out onto the transfer material and then the transfer material is bonded to the product using a heat press. Ideally, the transfer material will be cut right to the edge of the graphic so as to make it look like the graphic is printed directly to the surface.
Typically this type of transfer material is white, so it provides a neutral base for the ink to be applied to. In addition, white ink is not needed to print the color white, as that area of the graphic is left open and the white background shows through creating white space where needed in the design.
This method involves both printing and cutting, which can be done in two separate steps (print, then transfer the media to a cutter), or in one operation via a print-cut system which handles both steps sequentially with one piece of equipment.
When working with these types of heat transfers, it’s customary to create two separate art files. The first is of the graphic itself, which includes reference marks for proper alignment in the cutter. The second is a cut file while is used to drive the cutter. It’s critical that the printed transfer is lined up correctly in the cutter to ensure that the graphic is properly cut out to where no white material is visible around the edges.
Ultimately, the opaque transfer looks similar to the old style transfers of the past, but modern materials and equipment ensure that today’s version is superior when it comes to quality and longevity.
An ink transfer (sometimes referred to as a digital transfer) also requires heat but no adhesive backed material. The process begins by printing an image onto a sheet of commercial “release” paper using a supported inkjet printer loaded with special inks that are compatible with the material being decorated. The transfer paper is then placed on the garment and pressed with a heat press. The combination of heat and pressure causes the ink to transfer from the paper onto the garment. At the completion of the process, the transfer paper is removed and discarded, leaving behind an image that is imprinted on the fabric.
While there is no adhesive backing involved, ink transfers do rely on adhesives to bond to the fibers of the garment. In this application, the adhesives are either contained in the ink or on the surface of the transfer paper. The combination of heat and pressure activate the adhesives, known as binders, and complete the process of bonding the ink directly to the fabric. The transfer paper itself is only temporary and is never left behind on the garment. Only the ink and chemical binders make the transition.
The process is simple, quick and very inexpensive. You only need to invest in an inkjet printer, apparel ink, and a heat press, plus suitable design software such as Photoshop and CorelDraw. It’s worth nothing that you can’t just run down to the office store and buy any printer you see. The companies that manufacture the inks designate specific printers that can be used with those inks. But that doesn’t mean you have to purchase an expensive printer. There are several models that cost less than $300 that work just fine.
Digital transfers are not limited to inkjet printers. There are laser applications as well. In fact, there are quite a few different products available for different applications. It’s worth taking the time to explore the options as it’s important to match the decoration technique with the substrate to ensure the best transfer of color as well as reliable bonding.
Sublimation is a simple, but unique digital dye process used for printing graphic images onto polymer surfaces. The physical steps are pretty much identical to the ink digital transfer process, but it’s the chemistry that makes sublimation uniquely different from any other form of heat transfers.
Just like with ink transfers, the process starts by creating an image and printing it onto transfer paper using, in this case, sublimation inks. The transfer paper is placed on the substrate that is being decorated and heat is applied using a heat press.
The combination of heat and pressure cause the sublimation ink to convert into a gas which then permeates and attaches to any polymer based fibers it comes in contact with. The transfer paper is removed and discarded, leaving behind only the image. Unlike ink transfers, sublimation doesn’t require any binders or adhesives, as it bonds molecularly to polyester and polymers.
It should also be noted that the dye permeates the fibers and recolors them from the inside out, meaning you can’t feel the inks as they are not on the surface. The result is a high resolution, permanent coloration that won’t fade or crack, even after multiple washings.
Obviously the limitation of sublimation is that it only works on polymer-based surfaces, which, in the case of apparel, means some form of polyester. But with the surging demand for poly-performance apparel, sublimation is the ideal process to have in-house.
A key advantage of sublimation is that it is a simple process for decorating non-apparel items as well, including plaques, awards, coasters, signage, clipboards, mugs, mouse pads, photo panels, etc. In fact, the clarity and detail provided by the sublimation process make it possible to produce true photo-realistic images. Many professional photographers use it to create portraits and other photo products.
The startup and imaging costs are very low for sublimation, putting it in reach of any shop looking to expand its capabilities.
Diversify with transfers
As you can see there are many types of heat transfers, each with its own unique characteristics and applications. The deeper you look, the more variations you will find, with new products being developed routinely. Heat transfers are an excellent way to diversify any shop, but it will take some research to determine which products are right for your situation. To learn more, visit THE NBM SHOW and see some of the different systems in action. You can also take seminars that will give you a closer look at the options available to you. At the end of the day, it all adds up to increased opportunities to grow your business and make more money.