Walk Through of the Garment Printing Process
Artwork
To start any job, we begin with artwork. We will either create customers artwork, receive artwork from a customer, or more likely, some combination of the two. This is always an area of difficulty for screen printers. Most customers have little understanding of what kind of artwork we need, or what we as screen printers are capable of reproducing on a garment. So we are happy to help you understand just what it takes to produce a quality product
Film
Once we have finished and our customer has approved artwork, we’ll need to create a film positive. We use a film positive to burn the image onto a screen. There are a variety of ways to create a film, but most screen printers today will use an inkjet printer to output a clear waterproof acetate film.
Screen
The screen is a weak point in the chain for many printers, cutting corners and “making it work” when in fact the wrong mesh is used, improper tension, or both! Get your screens right, and you’ll be ahead of most of the competition. In the screen printing industry, you’ll hear debate about 1) wood frames, 2) static aluminum frames, and 3) retensionable frames. As with many things in screen printing, all will accomplish the task.
Coating
To make a screen ready for the press, we need to apply a photo-sensitive emulsion to the mesh. There are two primary options. The first is to apply a liquid emulsion to both sides of the screen using a scoop coater. This hand-held device is filled with emulsion, placed against the screen mesh and slowly pulled bottom to top, depositing emulsion as we go. The screen is then turned and the same process is repeated on the other side. The second option is to apply capillary film to a wet screen. Capillary film is in fact a dry emulsion on an acetate carrier sheet.
Exposing
Ultraviolet light (UV) is what exposes our emulsion coated screen. Sunlight is the perfect source of this UV light. That’s why we wear sunscreen! There are a variety of UV light sources available for you to use. The process in a nutshell is this: We place our film positive against the coated screen, and then expose it to UV light. Where the light touches the screen, the emulsion hardens. Where the light does not touch the coated screen (behind the black parts of our artwork), the emulsion stays soft. After exposing the screen to UV light, we remove the film positive and wash out the image with a gentle spray of water.
Printing Equipment
If you’ve ever visited screen printing shops or attended a trade show, you may have seen anything from one color manual machines to 14 color automatic presses. It all comes down to efficiency in the end. An automatic press is far better to print a 10,000 piece order, but that same automatic press is not your best choice to print a 24 piece job.
Inks
Most screen printers use only plastisol ink. If you have any printed T-shirts in your dresser drawer at home, they are likely printed with plastisol. There is a common assumption that only heavy, plastic-like prints are plastisol, but this is not the case. Plastisol can be printed with a very soft “hand”, and is the ink of choice in the industry due to it’s ease of use. Plastisol will not dry in your screen when you walk away for five minutes… or five days! A real advantage when you’re wearing all the hats in your business.
Squeegees
Squeegees come most commonly with a wood handle and a square plastic or rubber blade. Squeegees are purchased by the inch from your supplier, for all the different sized graphics you print. You will use a squeegee that is at least an inch wider than your image on each side. Squeegee blades come in different hardness, measured in durometers. Softer squeegees will lay down more ink, and harder squeegees lay down less.
Adhesives
An adhesive is needed to hold your shirt in place while you print. A low tack adhesive is used to lightly hold the fabric onto the shirt platen. Most printers will use a spray adhesive that comes as either a mist or web spray. There is also a liquid adhesive used in the industry as well.
Curing
All inks will need to be heat set. Plastisol ink needs to reach a temperature of approximately 320 degrees to cure. Your best option is to use a conveyor dryer. You lay the shirt, print side up, on the dryer belt and let it move into the dryer chamber. When the shirt exits the other end, assuming your dryer temperature and belt speed is correct, the garment is finished. You can wear it, wash it, fold it and box it. Once plastisol ink reaches curing temperature, it is completely cured, now and forever.
Relatively low world stocks of cotton; limited supply, robust demand and a very low level of uncommitted cotton caused the surge in prices in 2010/11. The Cotlook A Index surged from 86 cents per pound on August 2, 2010 to a record 186 cents per pound on December 22, 2010. 
