Step 1: Print the artwork and cut to size by trimming, die-cutting, or kiss-cutting.
Step 2: Apply to the shirt or other fabric. Remove the backing paper, cover with a sheet of parchment paper or another layer of light fabric or paper. Heat press or iron. When cool, remove the covering layer.
For years, commercial printers were busy and presses continually full with both small and large jobs as businesses counted on paper to advertise and promote their products, services, and causes.
Now, as organizations advertise themselves and sell their products and services directly over the Internet, as digital short runs have increased in popularity, and as environmentalists promote reducing paper consumption, the demand for commercial printing has abated.
Today, business savvy commercial printers are looking for opportunities to print on non-traditional (i.e.: non-paper) substrates such as fabrics. A key element of this strategy lies with a new generation of commercially available heat transfer papers that allow printing of simple to complex images on fabrics including soft signs, flags, canvas, denim, and t-shirts. This ability gives printers the opportunity to use their existing equipment, materials, and finishing capabilities with current and new customers to help grow their business.
Heat Transfer Papers 101
High quality heat transfer papers have been around since the mid 1990s, so forget about the crackling and peeling “iron-on” transfers of years ago. The first thermal and laser products were introduced in the mid 1980s, followed by inkjet products in the late 1980s, and the first dark transfers in the mid 1990s. Self-weeding laser heat transfer papers have been around since 2005.
Today, heat transfer papers are available for a variety of applications, from desktop digital to high-volume offset printing. Some of today’s heat transfer papers have better environmental and product safety advantages than others, so printers looking to adhere to higher green standards should look for heat transfer papers that do not contain the following harmful ingredients:
- PVC (Polyvinyl Chloride)
- PFOs (Perfluorooctane sulfonic acid)
- BPA (Bisphenol A)
Offset printing using heat transfer papers provides an economical, fast, and efficient way to produce heat transfers for decorating t-shirts, sweat shirts, canvas bags, canvas notebooks, and other fabrics. Printers can sell shirts or items with printed images to produce revenue, or printed images can be supplied to the consumer for application by hand iron. In addition to line art, photographs and photo-quality images may be applied.
When selecting heat transfer papers for offset printing, it’s important to use different papers for light and dark fabrics. Heat transfer papers for dark fabrics should prevent the dark fabric dyes from discoloring the art or graphics. Since it is often not known what color garment they will be applied to, the products for dark fabrics can be used on both and solve the issue of which one to use. Both types of papers should:
- Eliminate offset ink migration
- Prevent ink bleed when wet
- Withstand many wash and dry cycles with good color retention and no bursts or cracks
- Be applied by heat press or hand iron
Tips for Production
While today’s heat transfer papers are easy to print, pre-testing of all procedures prior to press is recommended to ensure the desired results. Offset printers should consider the following tips:
Prepress: Imagery should be adjusted in prepress to compensate for the additional 5-15% tone value increase that will occur. The precise amount of under color removal is image specific. Total print densities should not exceed 280%. Remember that many of the prepress proofs have fixed compensated dot gain for coated stocks.
Ink/Ink Drying: Inks with more tack will give a firmer dot, so low-solvent, high-solid inks are recommended. Anticipate a dry-back of five to seven density points.
Handling: Keep heat transfer papers wrapped in mill packages until ready to print. Pressroom conditions should be as close as possible to 68°F and 45-60% relative humidity. Printing in smaller lifts is recommended.
On Press: Today’s heat transfer papers have special surface treatment and uniform formation for excellent solid ink coverage and superior hold out. Most offset inks work well, but testing is always recommended prior to production runs.
Trimming and Die-Cutting: A sharp blade will ensure a clean cut through the stock, while a dull blade could tear the stock.
Be sure to print on the coated side of the heat transfer paper. If there are no lines or logos, scratch the corner of one side to see if the coating comes off under your nail. You can also compare color. The coating has a creamy color, but the back is usually whiter.
Some papers work well on almost all fabrics and blends, but when transferring to nylon or polyester fabrics, temperatures should be kept below 300°F to avoid migration of the fiber dyes into the transfer.
The first step is to peel the backer paper from the printed image and place the printed film face up on the garment. Once the image has been printed and peeled from the backer paper, it can be transferred to a cotton, cotton/poly blend, or synthetic garment using either a heat press or hand iron.
For heat press applications, press the imaged sheet onto the desired garment or substrate covered with a parchment sheet or other paper or fabric. Cool completely and remove the pressing sheet. Note that heavier fabrics, such as canvas, require more heat, pressure, and time.
For hand-ironing, preheat the iron to the cotton setting for three minutes for 8.5x11" transfers and proportionally less time for smaller areas. A 3x3" transfer requires about 15 seconds. Do not use steam. Iron on a smooth, hard surface that is waist level or below. Place a pillowcase or similar fabric on the surface and iron it to remove any wrinkles. Put the garment on the center of the pillowcase and iron it to remove wrinkles. Place the transfer with the image side up in the center of the garment with an ironing sheet (baking parchment or a thin layer of fabric, such as a single layer of sheet or t-shirt fabric) on top.
Using two hands, firmly slide the iron up and down. In 90 seconds, make enough passes to completely iron the shirt two times. The iron should be halfway off the edge when the edges are ironed. Repeat this 90-second process, sliding the iron side-to-side. After ironing, allow the transfer to cool completely before removing the paper.
Ask Your Paper Supplier
Your paper supplier can provide guidance in selecting the right heat transfer paper for your needs. Be sure to ask your supplier the following:
- What type of changes will I need to make in pre-press?
- How should art be managed? How does imagery need to be adjusted for tone value increases?
- Do I need to do undercover removal?
- What is the total print density?
- What should ink tack be?
- How should the papers be handled and stored?
- What lifts are recommended?
- What is the holdout and drying time?
- What is needed for trimming and die-cutting?
Commercial printers are ideally suited to compete with both desktop users and screen printers in using non-paper substrates such as fabric. They are skilled in color control and print production. They can provide exceptional detail and fine art applications, with the skill set to produce superior images. Plus, they have higher output capacity. Careful attention to production issues should put printers in a good position to increase their business volume using heat transfer papers.
Gerry Rector is the associate marketing director for heat transfer paper at Neenah Paper, Inc. Neenah Paper offers products for heat transfer papers for laser, inkjet, and offset printing. To learn more, visit www.neenahpaper.com.