You may have worn a screen printed t-shirt, or owned a poster or any other art work without even realizing it. It’s an amazing technique for creating custom printed clothing. This technique was originally used in creating vivid canvasses, posters and other art works. You could have heard names like serigraphy or silk screen printing which refer to the same screen printing technique.
What is Screen Printing?
It is a process of transferring a design, made on a stencil, onto a flat surface using a mesh screen, ink and a squeegee. Normally this is used on fabric or paper but with specialized inks all kinds of surfaces like wood, metal, plastic and even glass can be printed on. Essentially it involves creating a stencil of the design on a mesh screen and then subjecting it with the ink in such a way that ink passes through the mesh and onto the surface underneath creating an imprint of the design.
There are three types of stenciling techniques used mainly:
- Covering the desired areas of screen with a tape or vinyl
- Painting the stencil onto the mesh with screen blockers like glue or lacquer
- Using light-sensitive emulsion to develop stencil like a photograph
For multicolored designs, multiple stencils are used to apply color in individual layers.
Why Screen Printing?
Screen printing produces intense colors even on darker fabrics. Designs printed through this technique have a pleasingly tactile quality because of layering of ink on the surface. The other advantage is easy reproduction because a stencil can be used multiple times perfectly suited for mass producing t-shirt for sports teams and corporate event uniforms. There is only one major disadvantage and that is the limit on number of colors you can use in one design.
The Screen Printing Process
Below is the detailed process for screen printing:
- Step 1 – Create the Design
Print the design you want on the final product, on to a transparent acetate film. This film will be used to create the stencil.
- Step 2 – Prepare the Screen
Choose a mesh screen as per the complexity of the design and the texture of the garment being printed. Coat this screen with a layer of light-reactive emulsion which will further solidify under bright light.
- Step 3 – Expose the Emulsion
Lay the acetate sheet featuring the design onto the emulsion coated screen and then expose the whole thing to a very bright light.
- Step 4 – Wash off the Emulsion to Create a Stencil
Screen areas which are not covered by design become hard once the screen has been exposed for a set time. Any unhardened material needs to be washed off so that a clear imprint of the design can emerge on the screen. Dry the screen and do final touch ups to make the imprint look perfect. Your stencil is now ready to be used.
- Step 5 – Prepare the Garment for Print
Place the screen on the printing press and lay down the fabric on the printing board underneath the screen. There are mainly three types of presses – manual, semi-automatic and automatic, but most modern commercial printers will use an automatic rotary carousel printer, for ease of working with several different screens at once. For multi-colored prints, this sort of printer can also be used to apply the separate color layers in quick succession.
- Step 6 – Press the Ink through the Screen and onto the Garment
Add the ink to the top end of the screen and use a squeegee to pull the ink along the full length of the screen. This presses the ink downward through the openings in the stencil, imprinting the design on the product underneath. If you want to create multiple items, then raise the screen and place a new garment onto the printing board and then repeat the above process.
- Step 7 – Dry, Check and Finish the Garment
Pass the printed garment through a dryer to dry the ink and create a smooth, colorfast finish. Check and wash the garment thoroughly to remove any leftover material. Your printed garment is now ready.
Will Screen Printing Ink Wash Out?
If a cloth has been properly screen printed using a heat-treated washable ink, then the design should last many washes. To ensure a colorfast finish, you need to make sure that the ink is set as per the instructions of the manufacturer. The correct drying temperature and time vary depending on the type of ink and the fabric used, so you need to follow the instructions very carefully if you want to create a long-lasting, washable item.
How Screen Printing Differs from Digital Printing and Heat Transfer?
Digital printing uses a special fabric printer, very much like an inkjet computer printer, to transfer an image directly onto a fabric. Unlike screen printing, in digital printing, a printer is used to imprint the design directly onto the fabric. Without the limitations being posed by a stencil, multiple colors can be applied all at the same time, rather than in separate layers, meaning this technique is often used to print intricate and colorful designs.
Unlike screen printing, for digital printing very little setup is required, making digital printing a more cost-effective alternative for printing small batches of clothing or single items. And because it uses a computerized image rather than a stencil, it’s great for producing photographic or highly detailed designs. But, as the colors are printed using CMYK-style dots of color, rather than solid blocks of ink, it doesn’t provide the same vividness of color that you get with screen printing. You can’t achieve texturised effects with a digital printer, either.
Heat transfer printing is any kind of printing that uses heat to bind a design to a garment. In this type of printing you first print out a design onto a material coated with heat-reactive adhesive known as sublimation paper or transfer paper. When a heat press is applied to the transfer paper, the adhesive reacts to the heat and binds to the surface of the garment beneath, creating a printed garment. Heat transfer printing is simple and cost effective, so it’s great for smaller batches of printing. It can also be used to transfer detailed photographic designs, which are not possible through screen printing. Heat transfer printing can also be used to print on items with un-regular shapes like hats, bags, or shoes, which can be very tricky to screen print.
Often the heat transfer process is combined with digital techniques, to get the better effect. The digital heat transfer printing creates a design using computer software and prints it onto white transfer paper. The design is then cut out using a plotter machine, which follows a digital outline to achieve precision. The finished transfer is placed on the desired spot on the garment or accessory, and is then heat-treated to bind it to the fabric.
Pros and Cons of Screen Printing
- More suited for larger single or two color designs.
- Perfect for printing on the cotton and poly cotton clothes.
- Screen printed garments are machine washable as the ink is heat dried.
- The print created by screen printing is bright irrespective of the color of the fabric.
- The print can be ironed.
- Cost effective if printed in bulk.
- There is no limit on the size of the print and it is possible to do all over prints.
- Expensive if not printed in bulk.
- As each color is applied separately, the making cost gets higher with each addition of color.
- Separate screens are required for each color.
- Not ideal for multi-colored design.
- Not suitable for coated fabrics.
- The set up and cleaning required after each run is quite time consuming.
Pros and Cons of Heat Transfer
- Heat transfer printing is environment friendly.
- Printer has much greater flexibility and control in this type of printing due to the availability of specially formulated inks, advanced graphics and software packages.
- Possible to print multi-colored designs as long as colors don’t overlap.
- Inexpensive even for small runs of printing.
- Expensive to set-up and expensive to run large batches.
- Layering of colors is not possible as the printed cloth becomes bulky.
- The print is not very durable.
- Not many washes are possible as print may fade with wash.
- Not as sophisticated looking as a screen printed t-shirt.
- Can’t print on darker fabrics.
- The print is not very accurate.
- The print is not porous and may provoke sweating for the wearer.
- The print is not iron friendly.
Components of Screen Printing
Below you can find details about major components of screen printing:
A press allows you to print lots of items in a more efficient manner. Although you can print even with just a mesh screen and a squeegee, to get any kind of mass production going you must have a press. The press holds the screen in place between prints, making it easier for you to change the clothing being printed. There are three types of press: manual, semi-automatic, and automatic. Manual presses as the name suggests are operated by hand, resulting in a labor intensive process. Semi-automatic presses are partially automated, but still require human interventions to change the items being pressed, while automatic presses are completely automated and require almost no human intervention. If your business is very small and you want to keep it that way then the ideal type of press for you is manual. On the other hand if you have a large business that needs to print items in bulk, you will need a semi- or fully automatic press, as this allows for faster and more efficient printing.
The Silk Screen
The silk screen in screen printing is a metal or wooden frame with a fine mesh fabric stretched over the top. Traditionally, this mesh was created from silk thread, but nowadays polyester threads are preferred, which are much more cost effective. The thickness and thread count of the mesh must be decided on the basis of the fabric being printed. The narrower the gap between the threads in a mesh screen better will be the details of the print. A stencil is ready as soon as screen has been coated with emulsion and exposed. Once the printing is done, it can be washed and made ready for the next run.
A squeegee is a blade, almost always made of rubber, attached to a long handle which could be made of wood, metal or plastic. This blade’s primary function is to push the ink downward through the mesh screen. Normally the squeegee is of similar size to the frame of the screen for the best coverage over the screen. The fitness of the squeegee is often decided by the level of details in the design being printed. A firmer blade suits the printing of intricate designs with fine details whereas a softer blade is more suitable to less detailed designs.
The ink is actually what we see as color on the print, so in a way it’s the ink which makes the design come alive on the t-shirt or any other surface. The ink is pressed downward through the mesh and onto the t-shirt being printed. A lot of thought is put into choosing an ink and color of the ink is not the only criteria. There are several types of inks (e.g. puff inks, glittery inks, texturised inks etc) which can be used to create different effects on the finished product. Also different inks work in different ways on different fabrics. So type of fabric and the type of effect you want to have will also decide the ink type. To make the print machine washable a specialist ink is used which is then heat-treated to make a colorfast, long lasting product which doesn’t wears out in just few washes.