What Is A Screen Print Transfer?
Instead of traditionally screen printing directly onto apparel, screen print transfers are first printed onto a transfer paper using the same plastisol ink. The paper has a release coating that lets the plastisol ink peel off of the transfer and bond to the fabric.
Screen printing is proven technology that has been around for a very long time. The first images screen printed onto fabric took place over 1,800 years ago in China! Screen print heat transfers weren't invented until the 1960s.
Starting out in the apparel printing world can be intimidating. The options and jargon can be overwhelming. With HTV, sublimation, DTG, heat pressing, and screen printing it can feel like you are learning a new language. Don't worry, we'll help you learn the terms and know the most efficient printing method for your project.
Screen Print Transfer Benefits
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The more you produce the less cost per print.Economies of scale that are like direct screen printing. The more popular a design is, the better your profit margin. |
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Excellent quality.The same plastisol inks used to direct screen print are used to make transfers. Because the transfer is being printed onto a coated paper the edge definition and detail is often crisper than screen printing directly to fabric. |
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Adhesives for a variety of fabrics.Screen print heat transfers are made by mirroring the image. Then the design is screen printed in reverse print order onto paper with an adhesive applied to the back of the transfer. These adhesives make the heat transfer be able to apply to cotton, polyester, cotton-poly and other technical fabrics with excellent durability. |
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Press on demand flexibility.Instead of stocking printed garments, transfers can be applied to apparel to fulfill orders as they come in. One of the biggest challenges retailers face is having inventory that doesn't sell. Many ecommerce fulfillment models use screen print transfers to lower their cost and increase inventory flexibility. |
How To Make A Screen Print Transfer
Screens
It's called screen printing for a reason. To make a quality print, you need to make a quality screen. Each color in your design requires its own screen. For example, a 3-color design containing red, white, and blue would require a red screen, a white screen and a blue screen.
Screens are constructed of a wood or aluminum rectangular frame with a polyester (we stopped using silk a long time ago) mesh stretched across the frame. The weave of the mesh has tiny openings that allow the ink to pass through. Mesh comes in a variety of counts and are selected based on the detail complexity of the artwork and the desired thickness of the ink deposit.
The mesh count is simply the number of threads per inch in the weave. A 110 mesh, would have 110 threads vertically and horizontally in a one square inch of mesh. The mesh count combined with the thread diameter determine the amount of ink that can pass through that opening. A low mesh count like 60 or 86 would have fewer, larger openings for the ink to pass through, while a high mesh count like a 460 would have many small openings. Low mesh counts hold less detail while higher mesh counts hold fine detail. It's similar to TV resolution. A 1080 tv produces more detail than a 480.
If 460 mesh holds the most detail, why not use it for every application? Because the thickness of the ink deposit and the size of the solid particles in the ink are important. To make sure the fabric doesn't show through the image, the mesh opening needs to be large enough to make a sufficient deposit of ink. The mesh opening also needs to be large enough to allow the solid particles in the ink to pass through.
To create a stencil of your image the screen mesh is coated with a photosensitive emulsion. Emulsion is water-soluble until it is hardened by light. Each color in your image is separated into and outputted as a .tiff file that can be imaged directly onto the screen (new school) or made into a film positive (old school). The negative (non-printing) part of the stencil is exposed to light. After it is exposed, the screen is pressure washed and the emulsion in the positive (printing area) rinses away leaving behind a stencil of your image.
Plastisol Ink
Plastisol is made by combining a white powdery PVC Resin with a thick clear liquid called Plasticizer. The colors that you see come from mixing pigments into the ink. Plastisol needs to be heated to 300-330º F in order to cure (our fancy term for drying). We start every factory tour by warning not to touch plastisol because it won't dry and it won't come out of your clothes. Because plastisol does not dry or cure under room temperatures it is very shelf stable. Leftover plastisol can be stored and used for the next project. This eliminates waste.
Screen Printing
Transfer paper is loaded into an automatic printing press. Each screen is registered to ensure the colors in your design are perfectly aligned. Plastisol ink is loaded into the screen frame. A squeegee and flood bar are designed to work in tandem. As its name would suggest, the flood bar floods the entire screen with ink. The squeegee then pushes through the stencil depositing the ink onto the sheet.
Registration marks are added to the emulsion stencil along the outer edge of the transfer sheet. They serve as a quality control guide. These registration marks are cut off after the sheets are reviewed for quality.
Screen Print Transfer FAQs
Sublimation is a process that uses heat to dye polyester fabric. Sublimation ink is made from dye powder that is ground into a liquid. It dries back into a solid when it is printed on heat transfer paper. When sublimation transfers are heat pressed onto polyester fabric the solid ink sublimates into a gas that dyes the fabric.
The biggest advantage of sublimation is that it has a no hand feel on the fabric. There is no ink to feel on the surface because the actual fibers are dyed. The biggest limitation of sublimation is that it only works on white polyester fabric. You can't sublimate natural fabrics like 100% cotton or colored polyester.
Screen print transfers use plastisol ink to lock onto the surface of many types of fabric. Where sublimation is limited to polyester, screen print transfers can apply to 100% cotton, cotton-poly blends, polyester, and other technical fabrics like spandex or polypropylene.
Direct-to-film (DTF) is a recent technology that digitally prints a full color image onto a heat transfer film. The image is created by combining 4 translucent colors: cyan, magenta, yellow, and black (CMYK). After the CMYK is printed a white ink cartridge prints a white underbase to give the CMYK colors opacity. An adhesive powder is sintered onto the white underbase before the ink is cured. DTF tends to have a thicker hand feel than screen print transfers.
DTF is ideal for one-of-a-kind personalized prints or small batches (less than 50 units) of full color images. If a design is 1, 2, or 3 colors HTV or custom plastisol transfers are more cost effective. For more than 50 units of a full color image screen print transfers are typically less expensive. Full color screen print transfers use the same CMYK color theory for generating a full color image. he major difference is that instead of digitally printing the CMYK and White, they are screen printed. Where DTF has an ink cartridge for CMYK, custom transfers have screens with a very fine mesh count to hold the detail. The white underbase is also screen printed to give the print opacity and receive the sintered adhesive before the transfer is cured in a convey dryer.
Traditional screen printing has the reputation as the gold standard for high quality prints. There are three major differences between traditional screen printing and plastisol transfers. First, screen print transfers are an indirect method. Instead of printing directly to the fabric, the ink is printed onto a transfer paper. The second difference is that the underbase is printed last with plastisol transfers. The last difference is that adhesives can be added to the underbase. The adhesive makes it possible for the transfer to stick to a variety of fabrics. The additional adhesive can also lower the application temperature which is important when trying to print heat sensitive fabrics like polyester and polypropylene.
Try Before You Buy
Get your hands on real samples of each formula option you can apply, feel and wash test.