Dampening Solution

In the conventional offset printing process the dampening
solution is used to separate the image and nonimage
areas, that is, to prevent the transfer of ink onto
non-image areas of the printing plate. The dampening
solution consists mainly of water. Experience has
shown that in conventional offset printing the dampening
solution should have a pH value between 4.8 and
5.5 and the water used in the dampening solution
should have a hardness level of between 8 and 12° dH
(1.43 and 2.14 mmol/liter; 1 mmol/litre = 100 mg
CaCO3 per 1 liter water). Dampening solution usually
contains plate preservative agents, wetting agent, isopropyl
alcohol (IPA), buffer substances, and anti-microbe
additives.

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