Water-metachromatic laminate, and process for its production

A reversible water-metachromatic laminate which makes a latent image formed therein visible upon water being applied, comprising

• a support;
• a porous resin layer provided on the support and forming a front surface area of the laminate and having a binder resin to which a low refractive index pigment stands fixed in a dispersed state, the porous resin layer being non-transparent in a water-unabsorbed state and turning transparent in a water-absorbed state;
• and
• a non-transparent water-repellent resin layer so provided as to exist within the porous resin layer to be coexistent therewith to form said latent image within the porous resin layer;
• wherein, when no water is supplied to said water-metachromatic laminate, the whole front surface area of the laminate is non-transparent so that said latent image remains latent and non-visible, and
• when water is supplied to said water-metachromatic laminate, said porous resin layer inclusive of the whole front surface area absorbs the water and becomes transparent while the water-repellent resin layer repels water and remains non-transparent, thereby the surface of other area(s) of said support than the water-repellent resin layer becomes visible from through said front surface of said laminate while the water-repellent resin layer remains non-transparent, so that said latent image becomes visible by a contrast between the surface of the support at which no porous resin layer is located and the non-transparent water-repellent resin layer.