Scratch-off inks for printing
Scratch-off inks are a set of special inks and a varnish which are meant to cover up the layer containing an information and to be easily removable (revealing). It is comprised of 2 inks and a varnish.
The first ink is used for printing informational, key elements to this product.
Next, a transparent release varnish is applied on the first layer, and then the actual scratch-off ink, characterised by desired properties (coming off in rolls, not chips, appriopriate stability of effect over time, etc.) which has poor adhesion to the substrate, is applied on the release layer.
Scratch-off inks are sometimes overprinted with an ordinary ink in order to put on additional information and complete the protection from attempts to decipher the hidden information.
The right scratch-off ink should also be printed with an appriopriate layer thickness so that the information underneath stays sufficiently hidden.
Sets of scratch-off inks are used in printing lottery tickets, discount coupons, advertising materials, games and activities.