A proof is a sample representation of a final printed product. It may be supplied in electronic form at an earlier stage, or in printed form that will show the publication as it will be printed. This allows for colour correction of elements like images. The electronic form of proofing can be a PDF file. The printed form of proofing can be either:
- Digital – produced by inkjet or toner based technologies printed on digital press paper that might differ from the actual paper being used in an offset print run.
- Offset – produced by plates and printed on the same paper as being used for the whole print process. These are sometimes called ‘wet proofs’ because they use liquid ink.
Proofs are commonly printed on proofing sheets containing several pages of the book – not necessarily consecutive pages – printed on the one sheet side by side. A typical proofing sheet might contain up to 8 pages. The larger the book size the fewer pages can be printed on the proofing sheet. Publishers can specify which pages to include on the proof sheet e.g. page 6, page 12, page 104 etc.
Digital proof sheets are fast and cheap. Offset proofs are expensive and take more time to produce sometimes adding hundreds of dollars and weeks to the production process.
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