LithoGard DESENSITIZING OPV ( commonly referred to as Desensitizing Ink ) is a transparent, nearly-invisible coating that is applied in-line on a litho press to prevent the transfer of images from one layer of carbonless paper to another. LithoGard DESENSITIZING OPV can be directly applied to front or back side of carbonless stock from an unused printing unit, just like an overprint varnish. Damping can be used for a spot application, or a knock-out blanket flood coating can also be applied. LithoGard DESENSITIZING OPV uses a very special combination of stable chemical desensitizing agents that help to stop transfer of images from one layer of paper in a carbonless multipart business form to the next one below.

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Desensitizing inks and coatings are applied on-press to negate the “strike-thru” effect of carbonless paper used in multi-part business forms.

Carbonless paper uses micro-encapsulated dyes that are activated when the pressure of a ball point pen or a dot matrix print head smashes the tiny capsule and releases the invisible dye on to the layer of carbonless paper below. 

The ingredients in our desensitizing OPV neutralize this invisible dye, thwarting the chemical reaction that takes places normally when the invisible dye couples with the other chemical component that is deposited on the top side of the carbonless sheet underneath that is necessary to make the dye turn visible on the top of the carbonless sheet underneath. Thus, when the two chemicals collide, they react and you see an image. The desensitizer blocks this reaction.

Desensitizers are commonly used in large, multi-part forms where information needs to be masked. You can commonly see this in official forms and checks that large organizations send out via snail mail.

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It is strongly advised that if a fountain solution is to be used, that the pH of the fountain solution is either neutral or a mild alkaline one in order to preserve the effectiveness of the desensitizing agents used in this OPV. Using a fountain solution pH of less than 5.5 usually requires more of the OPV per square inch be applied, and that remaining LithoGard DESENSITIZING OPV be considered neutralized if allowed to remain in the fountain