Modern high-volume lithography
is used to produce posters, books, newspapers, and packaging —just
about any smooth, mass-produced item with print on it.
In this form of lithography, which depends on photographic processes,
flexible aluminum or plastic printing plates are used in place of stone
tablets. Modern printing plates have a brushed or roughened texture and
are covered with a photosensitive emulsion. A photographic negative of the
desired image is placed in contact with the emulsion and the plate is
exposed to light. After development, the emulsion shows a reverse of the
negative image, which is thus a duplicate of the original (positive)
image. The image on the plate emulsion can also be created through direct
laser imaging in a CTP (Computer-To-Plate) device called a platesetter.
The positive image is the emulsion that remains after imaging. For many
years, chemicals have been used to remove the non-image emulsion, but now
plates are available that do not require chemical processing.
|
|
Looking for lithography Lithographers, offset
lithography, printing, pressroom, printing presses, direct to plate,
quark, quark xpress, photoshop, illustrator, indesign, artpro, union
organizing, join a union, start a union, union information, how to
start a union, desktop publishing, typography, scitex, brisque, four
color printing, color separation, pre-press training, photoretouching,
web design, html, graphics, pre-press, amalgamated lithographers? Please scroll down.
|
|
Need Some Action - Place Your Ad Here - Find Out How |
|
|
|
Alphabetical Listings
|
|
Add a new listing Link Your Listing
Update a listing
Cant' Find it? |
|
|
A J Printing & Graphics
1350 Central Ave # 1, Santa Rosa, CA 707 525-8600
Anderson Lithograph Co
Sausalito, CA 415 331-1746
Benchmark Lithography
2875 Bardy Rd, Santa Rosa, CA 707 523-2838
Descalso Lithograph
2145 Francisco Blvd E, San Rafael, CA 415 454-4290
Expressions Lithography
135 10th St, San Francisco, CA 415 255-9600
O'Dell Printing Co
5460 State Farm Dr # 11, Rohnert Park, CA 707 585-2718
Performance Printing Center
65 Lovell Ave, San Rafael, CA 415 485-5878
San Anselmo Printing Ink
44 Greenfield Ave, San Anselmo, CA 415 453-3200 |
| |
| |
| |
|
Still can't find it?
Try searching our entire site, the San Francisco North Bay Area (
Marin, Napa, Sonoma and Solano Counties) and the world wide web below.
|
| |
|
|
The plate is affixed to a drum on a printing press. Rollers apply
water, which covers the blank portions of the plate but is repelled by
the emulsion of the image area. Ink, applied by other rollers, is
repelled by the water and only adheres to the emulsion of the image
area--such as the type and photographs on a newspaper page.
If this image were directly transferred to paper, it would create a
positive image, but the paper would become too wet. Instead, the plate
rolls against a drum covered with a rubber blanket, which squeezes
away the water and picks up the ink. The paper rolls across the
blanket drum and the image is transferred to the paper. Because the
image is first transferred, or offset to the rubber drum, this
reproduction method is known as offset lithography or offset printing.
Many innovations and technical refinements have been made in printing
processes and presses over the years, including the development of
presses with multiple units (each containing one printing plate) that
can print multi-color images in one pass on both sides of the sheet,
and presses that accommodate continuous rolls (webs) of paper, known
as web presses. Another innovation was the continuous dampening system
first introduced by Dahlgren. This increased control over the water
flow to the plate and allowed for better ink and water balance.
Current dampening systems include a "delta effect" which slows the
roller in contact with the plate, thus creating a sweeping movement
over the ink image to clean impurities known as "hickies".
The advent of desktop publishing made it possible for type and images
to be manipulated easily on personal computers for eventual printing
on desktop or commercial presses. The development of digital
imagesetters enabled print shops to produce negatives for platemaking
directly from digital input, skipping the intermediate step of
photographing an actual page layout. The development of the digital
platesetter in the late twentieth century eliminated film negatives
altogether by exposing printing plates directly from digital input, a
process known as computer to plate printing. |
| |
| |
|
|
| |
| Back To Top |
|
|
Also See:
Keyword Category
Index
|
