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Sheetfed vs Web Offset Printing Processes
Web Presses print on a continuous roll of paper that is later converted into specific sizes of paper. These presses move at very high speeds, use the same offset process, but print on both sides of the paper same time, squeezing it between the
two blanket cylinders. This eliminates the need for separate impression cylinders. Web presses are used for publications because they are more economical for longer press runs.
Both press types require very small dots to be reproduced very faithfully in order to carry the halftoning illusion to it's ultimate goal: the printed page.
Sheetfed Presses print on specific sizes of paper, one sheet at a time. Sheetfed presses can articulate much smaller halftone dots and heavier amounts of inks.
Images are burned onto a printing plate that is mounted onto a plate cylinder (P) containing images that get coated with ink (I) while dampener rollers (D) clean off excess ink from non-image areas. The press then transfers (offsets) those images onto a rubber covered blanket cylinder (B), before offsetting the images onto paper that passes between the blanket cylinder and an impression cylinder (I).