Screen Printing and Silk Screens

Screen Printing

What you need to know to master screen printing, from making their own printing devices to getting artistic works of art.

Screen printing

Screen printing is a direct method of printing in which we push ink through a mesh screen directly onto the surface receiving the image. The mesh fabric stretched on a frame acts as a carrier for a stencil. This way you can make a print in one color. To print a design with multiple colors, multiple screens must be made — one for each color of the design — and printed in registration with each other. Screen printing gives you control over every part of the process, and with some experience, you can achieve wonderful effects.

The main element of screen printing is the screen. It is a piece of mesh tightly stretched over a wooden or aluminum frame. There are cells on the mesh through which the ink can pass freely. For screen printing, some areas of the mesh are covered with an emulsion to prevent ink from passing through. In other areas, the mesh cells remain open. Ink flows through the open areas of the screen, leaving a printed pattern on the material below the screen. This is how the print is created. You can buy screens and screen-making materials from most craft or art stores.

Materials for making your own screen:

Mesh

The mesh density determines the resolution of your print. The lower the number of threads per inch, the finer the mesh, and the precise details can be printed. A fine thread-count mesh such as 200 holes per inch would be used for printing on paper, whereas a thread count such as 100 holes per inch could be used to print a T-shirt. Mesh comes in yellow, orange and white. These colors affect the way light diffuse when the screen is being exposed. Plain white mesh is fine for standard quality prints. Orange diffuses light the least, so it is used to print more detailed images.

Frame

Mesh is stretched on aluminum or wooden frames. Aluminum frames are lightweight, strong and durable. Wooden frames are nice and it's easier to make them yourself. If you are making a wooden screen yourself, keep in mind that the frame must be strong and resistant to deformation. It is important to have really stable corners. To prevent the wood from getting wet and deformed after washouts, it can be covered with a waterproof varnish. You can also buy premade wooden screens. They are stretched very tautly and are made of solid wood.

Photo emulsion

A light-sensitive photo emulsion is applied in a thin layer over the entire surface of the mesh. When the emulsion is dry, a film with opaque images is placed on the screen, which blocks the printable areas from exposure to light. Then burning the screen is performed - the screen is exposed to light for a certain time. Where the image on the film has blocked the light, the emulsion remains soft. Where the light hits the screen, the emulsion solidifies. The screen is sprayed with water. In places where the emulsion has remained soft, it is washed off and the holes in the screen mesh become open. It is through these holes that ink will be applied when printing.

Transparency film with artwork

The most commonly used positive films are transparencies films for printing on a laser or inkjet printer. You prepare your design on a computer and print it on such film. But you can also just draw an image with paint markers, ink on a brush or in a rapidograph pen. You can also cut out outlines from paper, or use objects such as leaves. The main thing is that your design turns out to be opaque in the places where we will print.

Light source for exposure

There are many different light sources you can use to expose or burn a screen. The more ultraviolet (UV) rays and power the light source has, the less exposure time is required. You can use sunlight, UV fluorescent lamp, metal halide lamp, or incandescent lamp. But different sources will require different exposure times.

Ink

You choose ink based on the material you are printing on. There are fabric inks, water-based eco-friendly paper inks, and toxic enough inks for printing on metal and plastic. If you use different colors, you can buy different shades of ink right away, or take primary colors and mix them.

Squeegee

A squeegee is a tool with which printing takes place. It is used to drag ink across the screen and push it across the mesh. The squeegee consists of a hard rubber or urethane blade inserted into a wooden or aluminum handle. Blades come in different hardness and shapes. Medium hard blade with square tip for almost any printing. You will need different sizes of squeegees for different screens. The squeegee should be slightly narrower than the inner dimension of the screen frame.