Архивы рубрики ‘Chemistry’


The term electrophotography encompasses the familiar techniques of photocopying and laser printing. In these printing systems, the ink is a toner, which is generally a powder consisting mainly of pigment, charge control agent, and a low melting binder. Toner printing systems use optical or electrical methods to form an electrostatic latent image to which the […]


The term reprography was first used around the 1960s to encompass the new imaging techniques, including xerography, electrofax and thermog­raphy, which were emerging at the time for document reproduction. Reprographics still refers to those newer imaging processes which may be distinguished from conventional printing techniques, such as lithogra­phy, flexography and gravure printing, and traditional silver […]

Near-infrared Absorbing Dyes

In recent years there has been growing commercial interest in compounds which absorb in the near-infrared region of the electromagnetic spectrum (i. e. beyond 750 nm), a region which formerly had been regarded mainly as a scientific curiosity, rather than offering practical application signifi­cance. Interest in this region emerged particularly as a result of the […]

Dyes in Solar Energy Conversion

There has been considerable effort over many years aimed at the develop­ment of the means to convert solar energy into electrical energy. The potential advantages of solar power are obvious. It utilises a non-dimin­ishing energy source and suffers little from the global environmental problems inherent in energy generation by nuclear fission or by the combustion […]

Laser Dyes

Lasers are devices which provide an intense, continuous source of ‘in­phase’ radiation. The term laser is an acronym referring to light amplifi­cation by stimulated emission of radiation. Traditional laser technology utilises a variety of inorganic materials to produce the required emission. Several different types of inorganic laser have been developed to emit either in the […]

Pigments for Microcolour Filters

Flat-screen displays, such as those used in miniature televisions and computer displays normally produce a multicolour effect by means of microcolour filters used together with thin film transistors and liquid crystals, commonly also with fluorescent back-lighting. Since the ob­server is directly viewing the source of the light, the process involves the use of additive colour […]

Dyes for Liquid Crystal Displays

Liquid crystals, commonly referred to as the fourth state of matter, are materials which are intermediate in character between the solid and liquid states. Unlike normal isotropic liquids, they show some time — averaged positional orientation of the molecules, but they retain many of the properties of liquids, such as the ability to flow. In […]


The rapid advances in electronics technology which were a feature of the latter part of the 20th century have had an immense impact on our lives. The numerous examples of these developments include the growth in the ownership and in the sophistication of personal microcomputers, the wide range of electronically-controlled goods which are now commonplace […]

Functional or ‘High Technology’ Dyes. and Pigments

The chemistry of the most important dyes and pigments used in the coloration of traditional substrates, including textiles, paints, printing inks and plastics, has been dealt with extensively in the previous chapters of this book. It is likely that this range of well-established products will remain for the foreseeable future as the most important materials […]

Pearlescent Pigments

Pearlescent pigments give rise to a white pearl effect often accompanied by a coloured iridescence. The most important pearlescent pigments consist of thin platelets of mica coated with titanium dioxide which partly reflect and partly transmit incident light. Simultaneous reflection from many layers of oriented platelets creates the sense of depth which is characteristic of […]