Write a note on different types of printing

Printing in today Worlds :
At present, off-set printing is the most popular system of printing where from small to large machines are in use. Besides, “letter press system” is also in use. “Lino Type” and “Mono type” machines are also used for composing of English matter. Moreover, “Screen Printing” is also in practice for Printing on hard surface like
plastic.

Off-set Printing :
This is a printing system in which matter is written on a transparent paper so that the light could pass through it. Instead of writing, the matter is composed on computer, its Print is taken on a transparent paper which is also called “Butter paper.” Whatever style is required and even if a picture is required to be printed, it is also be included with its positive films. By this way, a copy of printed matter is prepared on transparent paper, and a plate is prepared from this copy. In order to prepare a plate the copy is placed on a sheet plate which is already sprayed with required chemicals. This plate is now placed in a vacuum frame and for a few minutes light is allowed to pass through it. ‘In the result reflection of printed matter and picture transfers on this metal plate. This plate is washed with developer chemicals and reflections of matters become more visible. This plate is then affixed on a round cylinder of printing machine, which has several small cylinders, with the running of machines these small cylinders smear ink on the plate. The reflection of printed matter on this plate transfer on the rubber sheet of a lower cylinder in opposite form when the paper passes under this rubber sheeted cylinder it prints on it in right form.

Litho-Printing :
Before the introduction of “off-set printing” system, “Litho Printing” system was commonly used in developing countries. Most of the books, magazines and periodicals were printed by this system. In this system, the matter was written on a pre-chemical paper with a certain type of ink. This paper was placed downward on a metal plate and the plate was warmed from below resulting the matter to transfer on the plate in opposite form. By
fixing this plate in the printing machines, the matter was directly printed on the paper. Such printing did not give best result. Besides the copy was used only once. “Off-set printing” gives better results and its copy plate is preserved and can be used any time in the future. All our major national newspapers are printed by this system. Among the “off set printing” machines ROTA-Print, Hiedelberg, Solha and Roland are famous ones.
The machines which prints in one colour is called “One-unit Machine” and those with several colours are called “Multi-unit Machines”. Presently our national newspapers are printed on WEB-Rotary Machines of four units.

Letter Press :
This is the simplest way of printing, in which the pre-moulded words of lead are composed in the form of matter and are placed in a frame. This frame is fixed in a small machine. Such machines are called “Tradel Press” usually invitation cards, visiting cards and letter pads are printed on such machines.

Lino-Type and Mono-Type :
In this system, composing is done by such machines which contain molten lead. Whatever matter is typed by the operator the lead moulds those words accordingly. Lino-type machines produced individual words. The moulded words are given a stereo-form and placed in a printing machine. By these stereo-forms printing can be done very fast and in a large quantity.

Electronic Composing :
The typing and arranging of matter on computer is called “electronic composing.”
Nowadays all matter printed in national newspapers is composed on computer.  The sub-editor finalizes the matter and sends to computer room for composing. There are several typists who know how to operate computers and type the matter on terminal computers. There is a facility in computer that whatever is typed or composed not transfer on the paper at the same time but it is at the control of the operator to keep the
printed matter preserved in the computer.
The matter remains on the monitor of computer where the operator can read it and in the event of any mistake he can easily correct it. The major benefit of composing on computer is that once a matter is typed it can be altered time and time again. The matter remains visible on the screen and where it is required new words or new lines can. be added. If a whole paragraph is required to be transferred to other place that is also possible by computers. The computer gives us this facility to bring any part of the matter in “heavy rule” or “underline” it and wherever we want we can make headings. We can increase or decrease the space between lines and where required can make paragraph, can widen the lines or increase the’ size of page with just a press of few keys of the “key board”. All such alterations are done without spoiling the paper. There is no hitch in altering the size, paragraph or space. After all the necessary alterations, when we are stifled, we can take out the paper through printer after final checking.