Irreversible hydrochromic tinting inks for printing
Hydrochromic tinting inks come in two variations: tinting from colour to colour and from black to colour.
These inks tint the print, dye and colour it under the influence of water. Colour-to-colour tinting inks somewhat ‘tint’ the print with their own colour. The colour, when watered down, spills in the closest area to the print.
The starting colour of black-to-colour tinting inks is black. The print, dotted in black, tints red, yellow, or blue, when the water is added. Hydrochromic tinting inks are used, for example, for securing documents.
The black underprint immediately becomes colourful during the attempt to modify the document by using water. Tinting inks are most commonly used for printing colouring books for children.
Small user colours areas dotted with black or colour, using a paintbrush soaked with water, and thus, paints the picture this way.