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What is screen printing?
Screen printing is a printing process in which ink is transferred to a substrate via a stretched mesh. It is a versatile process that can be used to print on various types of materials, including paper, fabric, glass, plastic, metal, wood or ceramics.
⧗ reading time - 8 to 10 minutes ⧗
What is screen printing?
Screen printing, an ancient technique with roots in China, has over the years become a form of artistic expression and a method of industrial printing. Its versatility and usefulness have earned it a place both in art galleries and on the production lines of various sectors, especially the textile industry.
It is characterized as one of the planographic engraving processes (the matrix is flat). The screen printing matrix is a polyester screen tensioned evenly and fixed to a wooden or aluminum frame. The screen, which is made up of many threads, in its original state is permeable and allows ink to pass through. However, when it is blocked (paper, adhesive tape, emulsion, etc.), it does not allow ink to pass through.
In this sense, the screen printing process involves the application of ink through the screen, which is transferred to the substrate (paper, fabric, other) evenly with the help of an element called a squeegee. The matrix, which can be obtained by different methods, determines the areas where the ink is transferred.
A distinctive feature of screen printing is that it is printed in successive layers, i.e. each color is printed one at a time, allowing colors to overlap and new tones to be created.
This article explores the main stages of the screen printing process, from preparing the screens to applying them to various substrates.
Materials, tools and accessories
We'll start by presenting the main materials, tools and accessories that can be found in the screen printing process, the indirect method and the stencil method. Some are essential, while others can help improve your work.
The mesh is stretched and glued to a frame, ensuring even distribution of the paint.
Used to transfer the ink to the substrate via the screen printing screen.
Chemical solution used in the indirect method to engrave the matrix directly onto the screen.
Transparent sheet, printed or designed with the final artwork. Digital or analog.
Water-based, plastisol or UV. Different ranges: paper, fabric, plastic, other.
Essential for emulsifying screen-printing screens and applying them evenly.
Concentrated stripper, emulsion remover for all types of screen printing screens.
Paper used in the stencil method. It is thin, resistant, waterproof and washable.
Substrate
Any material we want to print on. Paper, fabric, wood, glass, other.
Hinges >
To attach to a base. Adjustable to different screen profiles. For precise recordings.
Print support
Printing machine, with or without vacuum. Or a simple base with its own hinges.
Spray adhesive >
For fixing substrates to printing bases. Textile and paper. Leaves no residue.
Others
Adhesive tape, spatula, sponge, acetate, scissors, x-acto, scratch paper, ruler, paintbrush, apron, jars, poscas (and/or china ink, oil pastels, charcoal pencils), scale, spray bottle.
InDirect vs Stencil Method
The indirect method and the stencil method are two different approaches to the preparation process. Both play an essential role in creating the matrix, which defines the areas where the paint will be transferred to the substrate.
The difference between the indirect method and the stencil method lies in the way the matrix is created.
The stencil method involves cutting out the desired mask and gluing it to the screen. While the indirect method uses screen printing emulsion, a light-sensitive substance, which allows the matrix to be engraved through the process of exposure to UV light. Both have their advantages, depending on the experience or complexity of the artwork to be reproduced.
Stencil method
The stencil method is known for its simplicity. It involves cutting out the desired matrix, which determines the areas where the paint will go. The stencil can be made of various materials such as paper, acetate or even vinyl. However, we advise that it be as thin as possible and easy to cut.
It can be created manually by cutting away unwanted parts with a scalpel (x-acto or scissors), forming a kind of "mask" that allows the paint to pass through selectively.
This approach is especially useful for simple, low-complexity projects. The details can be challenging to reproduce accurately. However, the accuracy of the end result can depend on the skill of the person cutting the stencil, as well as the person printing it.
To make the cutting job easier and allow for greater detail, you can also use a table-top cutting machine such as the silhouette e cricut.
Stencil Paper / Stone Paper
Our screen printing kit includes stencil paper, which is actually stone paper. It's a mineral paper produced without cellulose, PVC, water or chlorine. It is thin, resistant (but easy to cut), waterproof and washable, ideal for making reusable stencils.
Cradle to Cradle Certification (Silver).
Indirect Method
On the other hand, the use of emulsion is a more advanced and precise method of engraving the matrix. In this process, a light-sensitive emulsion is applied evenly to the stretched canvas.
The design we want to engrave has to be printed on an acetate. This acetate with the black print is called a photolitho, which is then placed on the canvas. When the screen is exposed to light, the emulsion hardens in the areas exposed to light, but remains softer in the areas covered by the black (opaque) spots on the photolitho. After the right exposure, the screen is washed and the water removes the areas where we want the ink to be transferred.
This approach offers greater flexibility in creating detailed images. Photoliths can be generated from digital images or drawings, providing exceptional accuracy in reproducing the final artwork. The indirect method also allows for more efficient mass production, as the engraving serves for many print runs. And the dies can be reproduced by repeating the engraving process.
How do I choose between the indirect method and the stencil method?
The choice between the indirect method or the stencil method will depend on the nature of the project. Simple projects with few details, or without a lot of resources, can benefit from the stencil method, as it is a more direct and accessible option. The fact that you have no knowledge or experience of engraving (with emulsion) silkscreens is an essential factor when choosing the stencil method.
However, for more complex jobs, where the need for fine detail is crucial, die engraving is the right choice, as it offers a wider range of creative possibilities and allows precise reproduction of final artwork with fine detail.
If you already have experience and the right conditions for screen-printing, it's more likely that you'll work with the indirect method.
In industrial environments, where production efficiency is essential, the use of the indirect method becomes practically indispensable to guarantee consistency and quality on a large scale.
In short, both are valid, each meeting the different needs and demands of specific projects. The choice between indirect method and stencil is a crucial aspect of the process, directly influencing the quality and complexity of the final print. Here are some pros and cons of each method.
Stencil Method vs Indirect Method: Pros and Cons
Stencil method
Pros
- Cheaper
- Less complex
- More sustainable
- Little preparation
- Can be done at home with few resources
Cons
- Small print runs
- Smaller detail
- Less resistance
INDirect method
Pros
- More detail
- Durability of the matrix
- High abrasion resistance (depending on the emulsion)
Cons
- More expensive
- Exposure to UV light
- Longer preparation time
- Needs more knowledge and experience
- Requires chemical solutions such as emulsion and paint stripper
Other methods?
Screen printing doesn't always use a matrix. In the case of monoprint, there is no matrix, the intervention takes place directly on the screen. In other words, we "paint" the screen, adding the ink using a brush or spatula. Once filled, the paint is dragged across the squeegee, transferring the result to the substrate.
The canvas can be filled to the maximum, in the desired print area, leaving no empty space. In this way, we get a design very similar to the one we "drew" when we filled the canvas with ink. If we leave empty spaces, the ink will be dragged and produce a similar effect on the substrate.
Versatility of screen printing
One of the most striking features of screen printing is its versatility. This technique adapts to a wide range of substrates, from paper to glass. It is used by artists, who explore screen printing as a means of creating graphic works, while industries use it to print on different types of materials and products, including textiles, labels and packaging.
It is possible to print on metal, glass and even ceramics (in various states of clay). For each material, attention must be paid to the type of ink used, which must be suitable for each type of substrate. But also to the type of squeegee and number of threads indicated.
Screen printing ink brands usually have ranges for different substrates. Mainly for paper, fabric and material that doesn't absorb ink, such as metal, plastic and glass.
Choice of material, depending on the substrate
The number of threads and type of squeegee should be chosen according to the characteristics of the substrate and/or the artwork to be printed. For substrates that absorb a lot of ink, such as fabric, you should use more open screens. For substrates that don't absorb ink, more closed screens, which allow less ink to pass through, are the most suitable.
Graphic work
Manual printing is still the norm. On paper, in a simpler way, or using manual printing machines. The machines may have a vacuum system, registration options and even a guided arm for squeegee support, but there is still a lot of manual work.
Stamping
In fabric, there are many options for manual printing machines, also known as carousel printers. There are models from 1 station upwards.
Industry
Although there is manual printing in the textile industry, due to the need to print large quantities, automatic machines are used. The screen preparation process may still be manual (but there are even emulsifying machines), but the printing is done by machines. These machines can have more than 10 stations (printing bases per color), which means they can print more than 10 colors on the same textile (t-shirt or other). You can see some examples at M&R, one of the largest manufacturers of screen printing equipment.
In addition, there are other support machines, such as drying units or T-shirt folding units.
Conclusion
Screen printing is an ancient printing process in which ink is transferred to a substrate (paper, fabric, other) by means of a stretched mesh, the screen. This versatile method is used on a variety of materials, from paper and fabric to glass, plastic and metal.
The article explores the stages of the process, from preparing the canvases to applying them to different substrates, highlighting the printing in successive layers, allowing for overlapping colors and the creation of varied tones.
The screen printing process involves two main approaches: the stencil method and the indirect method. The former, which is simpler and more accessible, consists of directly cutting out the desired matrix and is ideal for simple projects.
The second, which is more complex and more expensive, also involves more technical knowledge and material. It consists of engraving the matrix and is preferable for more elaborate projects. In the article we highlight the pros and cons of each method, considering cost, detail, resistance and complexity.
We highlight the versatility of screen printing, a process that adapts to a wide range of substrates and is used both by artists to create graphic works and by industries to print on a variety of materials. The choice of screen printing method, whether indirect or stencil, depends on the nature of the project, directly influencing the quality and complexity of the final print.
Serigraphy thus stands out as a valuable technique in both the artistic and industrial scenes, offering diverse creative and production possibilities.