Offset Printing
Basic Facts and Features
Offset printing applies wet ink to paper by means of a roller (blanket) that transfers the image from a metal plate. After you sign your proof ticket indicating the job is ready to print, it is 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 area, which is offset to a cylinder called the blanket, then onto paper.
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 multiple part forms (NCR), envelopes or panel card invitations.
- 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 time represents actual press time, and your estimated 3-week production time may be shortened considerably by returning your proof quickly. (See Tips.)
Requirements to Place an Offset Printing Request
You will have several choices to make before work can proceed with an offset printing request. The person delivering your printing request should be prepared to provide the following information:
- Quantity (Paper cannot be ordered until we can calculate how much will be required.)
- 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 the work is needed
Jobs placed without full information may not be produced within the normal 15 days. For example, if paper is not selected when the job is pl aced, your order may be delayed while paper is being delivered.
Selecting Paper and Ink
Publications and Printing can provide offset printing on almost any type 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.
A selection of text and cover weight paper is stocked in our facility.
Samples of paper 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 from suppliers.