|
Paper And Ink Testing
A variety of tests are used to determine ink and paper and paperboard quality, and to measure their interactions. They are necessary to balance print quality, cost, and wear on the press. Some of the important paper and ink tests are listed here: Paper test Paper and ink testing Tests for paper and ink interaction A variety of tests are used to determine ink and paper and paperboard quality, and to measure their interactions. They are necessary to balance print quality, cost, and wear on the press. Some of the important paper and ink tests are listed here: Paper test A wide variety of paper tests are available, depending on the specific needs and on the governing contract or specification:. Major paper properties are widely classified into four categories. Physical Properties Optical Properties Mechanical Properties Miscellaneous Properties Physical Properties Grammage or basis weight Thickness Bulk Porosity or Roughness Dimensional stability Grammage Test The mass per area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including printing, painting, graphics, signage, design, packaging, decorating, writing, and cleaning. It may also be used as filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, or currency and security paper, or in a number of industrial and construction processes. The papermaking process developed in east Asia, probably China, at least as early as 105 CE, by the Han court eunuch Cai Lun, although the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preservation (library And Archival Science)
In Library science, library and archival science, preservation is a set of preventive conservation activities aimed at prolonging the life of a record, book, or object while making as few changes as possible. Preservation activities vary widely and may include monitoring the condition of items, maintaining the temperature and humidity in collection storage areas, writing a plan in case of emergencies, digitizing items, writing relevant metadata, and increasing accessibility. Preservation, in this definition, is practiced in a library or an archive by a librarian, archivist, or other professional when they perceive a record is in need of maintenance. Preservation should be distinguished from interventive Conservation and restoration of books, manuscripts, documents and ephemera, conservation and restoration, which refers to the treatment and repair of individual items to slow the process of decay, or restore them to a usable state. Preventive conservation is occasionally used int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wet-on-wet
Wet-on-wet, or ''alla prima'' (Italian, meaning ''at first attempt''), direct painting or au premier coup, is a painting technique in which layers of wet paint are applied to previously administered layers of wet paint. Used mostly in oil painting, the technique requires a fast way of working, because the work has to be finished before the first layers have dried. Technique Traditionally, a new layer of oil-based paint is applied to most parts of a painting only after allowing a previous layer to dry completely; this drying process can take from several days to several weeks, depending on the thickness of the paint. In contrast, work performed using ''alla prima'' can be carried out in one or more sessions (depending on the types of paint used and their respective drying times), and it is common for such a work to be finished in only one session or "sitting". In the medium of watercolors, wet-on-wet painting requires a certain finesse in embracing unpredictability. Highly trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the internal frictional force between adjacent layers of fluid that are in relative motion. For instance, when a viscous fluid is forced through a tube, it flows more quickly near the tube's axis than near its walls. Experiments show that some stress (such as a pressure difference between the two ends of the tube) is needed to sustain the flow. This is because a force is required to overcome the friction between the layers of the fluid which are in relative motion. For a tube with a constant rate of flow, the strength of the compensating force is proportional to the fluid's viscosity. In general, viscosity depends on a fluid's state, such as its temperature, pressure, and rate of deformation. However, the dependence on some of these properties is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inkometer
An inkometer is a specialized measuring instrument used by the printing industry to measure the "tack" ( adhesiveness) of an ink with the roller system on an offset press. The importance of tack is that it is not so excessive that it doesn't allow effective transfer from the rollers to the plate and then to the blanket and onto the substrate being printed. Inks can also be tack "graded" in descending sequence to allow for better trapping of one color over another. Inks with too much tack can cause the surface of the paper to pick off and interfere with transfer on subsequent printing units and copies. The amount of tack can be controlled by changing the amount of solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ... or other diluent used in the ink. The inkometer is made up of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substrate (materials Science)
Substrate is a term used in materials science and engineering to describe the base material on which processing is conducted. This surface could be used to produce new film or layers of material such as deposited coatings. It could be the base to which paint, adhesives, or adhesive tape is bonded. A typical substrate might be rigid such as metal, concrete, or glass, onto which a coating might be deposited. Flexible substrates are also used. With all coating processes, the condition of the surface of the substrate can strongly affect the bond of subsequent layers. This can include cleanliness, smoothness, surface energy, moisture, etc. Some substrates are anisotropic with surface properties being different depending on the direction: examples include wood and paper products. Coatings Coating can be by a variety of processes: * Adhesives and Adhesive tapes * Coating and printing processes * Chemical vapor deposition and physical vapor deposition * Conversion coating :* A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printed Sheets
Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The earliest known form of printing as applied to paper was woodblock printing, which appeared in China before 220 AD for cloth printing. However, it would not be applied to paper until the seventh century.Shelagh Vainker in Anne Farrer (ed), "Caves of the Thousand Buddhas", 1990, British Museum publications, Later developments in printing technology include the movable type invented by Bi Sheng around 1040 AD and the printing press invented by Johannes Gutenberg in the 15th century. The technology of printing played a key role in the development of the Renaissance and the Scientific Revolution and laid the material basis for the modern knowledge-based economy and the spread of learning to the masses. History Woodblock printing Woodblock pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid-free Paper
Acid-free paper is paper that, if infused in water, yields a neutral or basic (chemistry), basic pH (7 or slightly greater). It can be made from any cellulose fiber as long as the active acid pulp is eliminated during processing. It is also lignin- and sulfur-free. Acid-free paper addresses the problem of Preservation (library and archival science), preserving documents and Conservation (cultural heritage), preserving artwork for long periods. Overview Paper made from wood-based pulp that has not had its lignin removed turns yellow, becomes brittle, and deteriorates over time. When exposed to light and/or heat, the molecules in the acidic paper will break down even faster. Acidic wood-pulp paper became commonplace in the late 19th century, and in the 1930s William Barrow (chemist), William Barrow (a chemist and librarian) published a report about the deterioration of acidic paper in the libraries. For fear of the gradual disintegration of written materials, measures have since ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lignin
Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily. Chemically, lignins are polymers made by cross-linking phenolic precursors. History Lignin was first mentioned in 1813 by the Swiss botanist A. P. de Candolle, who described it as a fibrous, tasteless material, insoluble in water and alcohol but soluble in weak alkaline solutions, and which can be precipitated from solution using acid. He named the substance “lignine”, which is derived from the Latin word '' lignum'', meaning wood. It is one of the most abundant organic polymers on Earth, exceeded only by cellulose. Lignin constitutes 30% of non-fossil organic carbon on Earth, and 20 to 35% of the dry mass of wood. Lignin is present in red algae, which suggest that the common ancestor of plants and red algae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paperboard
Paperboard is a thick paper-based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker (usually over 0.30 mm, 0.012 in, or 12 Inch#equivalences, points) than paper and has certain superior attributes such as foldability and rigidity. According to International Organization for Standardization, ISO standards, paperboard is a paper with a grammage above 250 g/m2, but there are exceptions. Paperboard can be single- or multi-ply. Paperboard can be easily cut and formed, is lightweight, and because it is strong, is used in packaging. Another end-use is high quality graphic printing, such as book and magazine covers or postcards. Paperboard is also used in fine arts for creating sculptures. Sometimes it is referred to as ''cardboard'', which is a generic, lay term used to refer to any heavy pulp (paper), paper pulp–based board, however this usage is deprecated in the paper, printing and packaging industries as it doe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
