Printing methods paper types

Not all papers tone equally well, and color effects can be harder to achieve with some paper/toner combinations than with others. Others may respond well to one toner and not another. Also, the color of a toned print depends on the formula of the toner and its dilution the paper type, surface, and paper base tint and not least of all the processing method. This last includes not only the print developer used but often the choice of fixer. 

Letterpress, Flatbed, Sheet Fed This is one of the oldest printing methods wherein direct contact is made between raised type, usually metal, and the facestock. The quality of the printing would be rated as fair to good since control of the ink is not as positive as some of the other methods. It should be considered for very short run paper stock where copy is fairly simple. The label stock usually used is a standard Crack/Peel type with very little selection of the adhesive. This type of factory-cut liner is more difficult to remove than other t5q)es, particularly for a large label. Not recommended for vinyls or other exterior grade use. 

Letterpress printing The process used for paper is adapted to plastics by the use of special inks and transfer rolls, and possibly a modification of press speed. Flexible printing plates are usually employed, made of vinyl or rubber. It is the oldest method of printing flat plastic substrates and uses a press for rehef printing ffom metal type or raised surfaces formed ffom wood, metal, or linoleum. Leach RH, Pierce RJ, Hickman EP, Mackenzie MJ, Smith HG (eds) (1993) Printing ink manual, 5th edn. Blueprint, New York. 

After registration of samples and their requirements, work-lists can be printed on paper or in files. There are various types of worklists. A list can contain all requirements for a sample (sample related). Another type comprises all samples for an analytical method (method related). A third one contains a matrix of some requirements which are measured at a work place with one or more instruments, and all relevant samples. A copy of this worklist is held in the LIMS for the entry of results. This kind of list has a fixed sequence of samples. 

The conditions to be met in decorative printing are particularly demanding. Decorative papers for gravure and flexographic printing are used to produce laminated plastic sheets. Pigment selection is a matter not only of the type of resin (melamine or polyester), but also a function of the processing method. 

True paper was invented in China by a court official, Gai Lun, in the year 105. Cai Lun found that by treating cotton rags in a certain way, the material would break down into a mushy mass of fibers. When more water was added, the mixture could be pressed and dried into a thin, hard sheet that could be used for writing. This true paper became popular because it was much lighter than bamboo mats and less expensive than silk, both of which were used as writing materials at the time. Gai s method of making paper eventually made its way to Europe, where it became the material of choice for use with the printing press in the fifteenth century. Industrialization and mechanization since that time have led to the modern paper industry and to the thousands of types and forms of paper that are a basic commodity of modern society. 

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