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• HEATSET: In web offset
presswork, using a gas- fired, hot-air oven to "set" the ink as the
paper moves from the printing units to the delivery end of the press.
--overcomes the problem presented by the high speed of
the web press, which does not give enough time for drying by absorption
--imparts high gloss to printing on coated stocks
--the addition of the oven makes the press longer; adds
to energy requirements
--suspected by the EPA of increasing the emission of
VOCs (volatile organic compounds)
• NON-HEATSET (a.k.a. "coldset"):
Printing on paper that does not need heat in order to dry properly. Web
presses set up to run publications on uncoated paper do not need the
oven, because uncoated paper is absorbent and dries readily.
• UV/EB: Setting
web-printed ink by "curing" it with ultraviolet or electron-beam
radiation.
--gives very high gloss, scuff resistance , and richness
of color
--needs specially formulated inks; electric power
requirements are high
--crews must be protected from UV/EB hazards
• What about sheetfed?
Sheetfed lithography is by nature a non-heatset process, although a
pressroom aid known as anti-offset spray powder is sometimes used to
speed the drying of printed sheets.
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