body | color | collections | commodity | cube | document | fabric | fetish | gender | glass | home | identity | living | machine | metal | minimal | mobility | narrative | olfactory | organic |
pain | paper | plastic | plugs | power | protective | rectangular | ritual | round | sound | souvenir | spiritual | style | text-based | time | tool | touch | uniform | value | visual | warm | wood
|Maps, Receipt, and Informational Handouts|
The paper was made from pulp obtained by chemical means, known as kraft pulping. Chips of wood were placed in a large, sealed container known as a digester. The digester contained a strongly alkaline solution of sodium hydroxide and sodium sulfide. Bleaching removes lignin and involves mixing the pulp with a series of oxidizing chemicals that react with the lignin. After each mixture, the pulp was washed with an alkaline solution that removes the treated lignin. Fillers were added to the pulp. (A typical filler is a clay known as kaolin. Other chemicals often added to pulp include starches or gums. Rosin and alum are often added as sizers, making the paper less absorbent.) Pulp was added to water to form slurry in order to make paper with an even density. The slurry was pumped onto a moving mesh screen made up of very fine wires of metal or plastic. Water drained through the small openings in the mesh, and formed a sheet of wet material from the slurry. The sheet was moved on a series of belst made of felt containing wool, cotton, and synthetic fibers. The dried sheets moved between rollers known as calendars to make it smooth.
Printed on sheet-fed perfecting offset printers. A lithographic press uses principles of lithography to apply ink to a printing plate, as explained previously. Sheet-fed litho is commonly used for printing of short-run magazines, brochures, letter headings, and general commercial printing. In sheet-fed offset, “the printing is carried out on single sheets of paper as they are fed to the press one at a time.” Sheet-fed presses use mechanical registration to relate each sheet to one another to ensure that they are reproduced with the same imagery in the same position on every sheet running through the press.
Color printing inks are made primarily with linseed oil, soybean oil, or a heavy petroleum distillate as the solvent combined with organic pigments. The pigments are made up of salts of multiring nitrogen-containing compounds (dyes), such as yellow lake, peacock blue, phthalocyanine green, and diarylide orange. Inorganic pigments also are used in printing inks to a lesser extent. Some examples are chrome green (Cr2O3), Prussian blue (Fe4[Fe(CN)6]3), cadmium yellow (CdS), and molybdate orange (a mix of lead chromate, molybdate, and sulfate). Black ink is made using carbon black. And white pigments, such as titanium dioxide, are used either by themselves or to adjust characteristics of color inks. Inks also contain additives such as waxes, lubricants, surfactants, and drying agents to aid printing and to impart any desired special characteristics. Printing ink is a $10 billion global industry. The Census Bureau tracks about 250 printing ink companies in the U.S., which in 1997 produced 2.2 billion lb of ink with sales of $4 billion.