Basic Facts and Features
Offset printing applies wet ink to paper by means of a roller and blanket that transfer the image from a metal plate. After you sign your proof ticket indicating the job is ready to print, your pages are output to negatives in the pre-press area via the Agfa Imagesetter. The image from the negative is then transferred to a metal plate by a photographic process. The plate is chemically treated to accept ink only on the image areas. Ink is offset onto a cylinder called the blanket, then onto paper, hence the name "offset printing."
When is Offset More Practical than Quick-Copy?
Your job will be run on an offset press when:
- The quantity makes it more cost effective to print more than one copy per impression. The offset press can print as many as 16 pages on one sheet.
- There are envelopes, raised panel cards, or multiple part forms (NCR). However, new technology allows some NCR to be quick copied.
- The job requires a paper size or type unavailable through the quick-copy process.
While most Xerox duplication requests can be produced in 24 hours or less, offset printing requires more time because of the setup required (including pagination, proof reading and preparation of printing plates from negatives). Less than one-third of the scheduled production time represents actual press time, and your estimated 3-week production time may be considerably shortened by returning your proof quickly. (See Tips.)
How to Place an Offset Printing Request
You will have several choices to make, and the person delivering your printing request should be prepared to provide the following information:
- Quantity (Needed early in the process so that the correct amount of paper can be ordered)
- Type, color and weight of paper
- Ink colors
- Method of binding
- Account number to be charged
- Person and extension number to be called when proofs are ready
- Date and time you will need the printing
Jobs placed without complete information may not be produced within the normal time frame. For example, if paper is not selected and quantity established when the job is placed, your order may be ready for the press but waiting while paper is being delivered.
Selecting Paper and Ink
Publications and Printing can provide offset printing on most types of paper stock including bond, book, text, cover, index, tag, pressure-sensitive carbonless, gummed labels and Kraft envelopes; or any finish, including matte, coated, vellum, linen, parchment, woven, laid, etc.
The most often-used text and cover weight paper is stocked in our facility. Samples of other papers can be reviewed in books available at the front desk. Paper orders are placed and delivered daily. P & P also maintains a substantial inventory of ink. An ink selector showing the various stocked ink colors is available at the front counter. Special order inks can also be obtained for you. Cost is usually about $50 per can.