What is Silk Screening?
Silk screening, or silk-screen printing (serigraphy), is one of the most preferred printing techniques by printing companies. It is a very old technique, dating back to at least a 100 years in the printing industry.
Silk screening is most commonly used in the printing process of various types of designs and images onto the fabric or other materials such as plastic, paper, cloth, wood, and others.
How Does Silk Screening Work?
This method involves the creation of a printing frame in automatic machines to help pull the ink and transfer the printed image from a sheet to the final medium or substrate material.
This printing frame is placed on top of the medium, and various screens with a specific mesh count having different colours to be printed are placed on top of each other in layers.
The ink color is then transferred onto the medium material with the help of a scraper tool.
With advancements in the screen printing process, better thick inks and machinery have been developed that allow us to produce images of high quality.
The Advantages of Silk Screening
There are many benefits of silk screen printing, which is why this method is so popular.
1. To begin with, silk screening is perfect for large runs where there is a huge number of prints to be made like tshirt printing.
2. Silk screening produces excellent quality at costs that go lower as the number of prints increases.
3. Silkscreen printing allows you to perfectly replicate your design, no matter what colours or patterns are present.
4. This method of printing ensures that personalised items last longer, without the print fading or wearing off easily.
5. The resultant print can be washed and used many times (in the case of fabrics), without the image becoming dull or faded.
Silk Screening Vs Digital Printing
When you compare screen printing vs digital printing, both methods of printing have their own unique benefits and drawbacks.
Silk screening, as mentioned earlier, is perfect for a larger number of prints, but is limited to a maximum of 4 unique colours in the design. This makes it more suitable for simple graphic designs such as logos and text.
It has high colour and line precision and produces sharp and intense images.
Digital printing, on the other hand, is more economical for fewer prints and can be done for complex images like high-resolution photographs.
The resultant prints are soft, without any protrusions or rough finishes.
For bulk printing and high contrast simple graphics and images, silk screening is your best option.
How is Silk Screening Done? The Step By Step Process
Step 1: Overlay Screen With Emulsion
The screen used in silk screening is a piece of sheer fabric.
The fabric initially used in ancient times was silk, giving the process its name. However, these days, polyester is the preferred fabric.
The screen is first coated with a photo sensitive emulsion such as diazo photo emulsion. This is a very delicate process and must be done in a dark room with no light.
The screen is then left to dry in the dark room without the light source.
Step 2: Burning The Screen
The screen is then burned by placing in front of a light source a transparent plastic sheet with holes that are cut into it in the places that the ink needs to appear.
The cutting of these holes can either be done manually or by using ultraviolet light (UV) in exposure units.
The plastic sheet is secured in place using tape, and the screen that is coated with the photosensitive emulsion is then exposed to light to “burn” it.
Step 3: Rinsing
After the screen has been burned, the transparent plastic sheet is taken out and the screen is gently rinsed in water.
The emulsion that previously had the image will be completely washed out. The screen then needs to be carefully set aside the screen to dry.
Step 4: Securing and ‘Pinholing’ The Screen
The screen needs to be secured to the printing frame with strong tape and checked for any areas where the emulsion may have been washed out by mistake.
Cover these washed out ‘pinholes’ with dark tape to prevent leakage of ink onto these spots that are originally not part of the design.
The screen is now ready to be set up in the screen press.
Step 5: Printing
Once the screen is nicely lined up and screwed into the press, it’s time to make the first print.
The coloured ink is taken and spread across the screen to completely cover the image.
A squeegee is then pressed and run over the ink at a particular angle to ensure that the ink correctly goes through the screen, and onto the medium below.
The process is repeated in case there are multiple coloured inks that need to be used to form the final image. The order of the coloured inks usually starts from the lightest colour and moves on to the darkest.
Once the first print is done, the print is checked for any errors in placement of the screen, before moving on to the next piece.
Step 6: Setting The Ink
Once the print has been successfully made, the piece is kept aside carefully for drying or curing of the ink.
This step will differ depending upon the type and the amount of ink used in the silk screening process.
Types of Ink Used in Silk Screening
There are different types of inks used in silk screening according to the effect that is desired. Apart from diazo photo emulsion/ sensitive emulsion/ photo emulsion, here are some of the types of printed inks that are used in station screen printing:
Also known as caviar beads, glue beads are printed direct to garment in the shape of the design, and small plastic beads are then stuck to it.
This creates a projected surface that can be physically felt.
These inks are used in screen printing while printing onto mostly dark coloured fabrics to discharge the colour that is already present in them.
They work only on pure cotton fabrics and require a well-ventilated room during application. This is because there are unpleasant fumes that are released during the application and heat transfers curing processes.
Discharge inks are usually used to discolour dark fabrics in order to print ink color designs on top of them.
Puffed ink creates a 3d printing look and feel to the surface. It is added to plastisol inks and is mostly used during silk screen printing on garments like custom tshirts.
Foiling is done by applying a thin sheet of metallic material on the surface using heat transfers in the screen printing machine.
- CMYK Coloured Inks:
This type of printing is done when more complex colours need to be silkscreen printed using the station screen.
Using only 4 screens, a huge number of different colours can be produced, thereby saving time and money in these printing techniques.
Metallic flakes or glitter is added to the ink base in the printing machine to give the design a sparkling effect.
- Glossy Ink:
Gloss is actually a type of finishing in screen printers, where a thin layer of clear base is applied over the design to create a glossy look.
Similar to glitter ink, metallic ink also has tiny particles of metal suspended in the ink that is used in the printing press on top of the screen.
The difference lies in the size of the metallic particles. Metallic inks have nano- sized metal particles.
This is the most common type of ink used for printed image in silk screening. It has a plastic-like texture, and can be made softer or heavier, depending upon the layers of ink that are added to the design.
They require high heat to set or cure the design once it is finished.
These days, a new type of PVC and phthalate free ink is being used, that is very similar to plastisol inks, but without toxic components present in it.
Water Based Inks:
As the name suggests, these inks are made with water as a base.
The ink easily seeps into the fabric, creating a very soft texture. It is usually used for commercial screen printing dark colours on lighter coloured surfaces.
Silk screening is one of the best methods for printing onto a variety of materials such as fabric, metal, plastics, and paper.
Screen printing presses are used for silk screening tshirts, printing tshirts and creating custom tshirts, garment printing, commercial screen printing, fine art, 3d printing, graphic design, etc.
Contact Unipipes Malaysia for more information.