Screen printing is an ancient printing technique that has been in fashion in all the time eras. In earlier times, printing was done by a woven mesh that supported an ink-blocking stencil. With the advancement in industrial technology, the general methods of printing have been modified but the basic concept remains the same.
According to the scriptures of written history, this technique has foundation roots in China during the Song dynasty (960-1279 CE). In the later times, this technique was also adopted by the Asian countries that brought innovations in it by combining it with block printing and paints. On the other hand, these printing trends weren't much in use in Western Europe where it was introduced in late 1700's and was scantly used for just printing wall papers or the other fabrics.
With the passage of time this field got sufficiently established and by 1910 people started experimenting to further refine the technique. The use of photo-reactive chemicals became common. These were experimented by utilizing actinic light and also the cross linking and hardening properties of sodium, potassium and ammonium bicarbonate chemicals in combination with certain gelatin compounds. The use of chromic acid salt sensitized emulsions for manufacturing the photo-reactive stencils was introduced by Charles Peter, Edward Owens and Roy Beck. These developments revolutionized the printing industry and with theses advancements later photo-imaged stencils paved way in the industry.
Later on in 1928, Joseph Ulano established he chemical supplier industry known as Ulano. He brought forward the method of applying a polish/gloss soluble stencil material to a removable base and this stencil was cut in various shapes and designs. In this way the printed areas were removed and the remaining material was left sticking to mesh. This helped in creating a sharp edged screen stencil which has numerous benefits in printing industry.
In the beginning screen printing was used only for industrial purposes but later on many artists adopted it as a medium of exhibiting their creative talent. According to the Printer's National Environmental Assistance Center screen-printing is definitely the most multipurpose and versatile form of all the printing techniques.
Now coming out of the history pages to the present times, the printing process is certainly much altered. Now in the printing technique the screen is made up of delicately woven fabric mesh which is fixed on a frame of wood or aluminum. The mesh is made up of any hard metal like steel or else polyester or nylon. For framing the motive, the areas of screen which are not to be printed are blocked off completely with any non porous material. In this way the negative of the motive is formed and the impression of the design is printed on the cloth.
The screen is fixed on the top of the fabric or cloth to be printed. An ink fill bar commonly known as the flood bar is used to inject ink in the open porous spaces of the stencil. The process is initiated form the fill bar at the back of the screen just behind the ink storage. The screen is lifted and by pulling the fill bar to the front of the screen the mesh holes are filled with ink. The mesh is then placed on the fabric or cloth with a rubber blade. The ink is pumped on the substrate by pushing the rubber blade at the back of the screen. The ink is squeezed on the cloth in controlled manner keeping the amount of pumped ink in accordance with the thickness of mesh. As the rubber blade is pulled towards the back of the substrate the mesh snaps off the cloth leaving a fine print on it.
Many companies use custom printed bags as a tool of marketing their products by getting their logos and promos printed on t- shirts. Screen printing can also be done on electronic and medical devices as well. This industry has a bright future and its use for marketing or simply getting exclusive unique dress range is expanding day by day.