dispersion or emulsion to the surface of the sheet and dried adhesive may be applied at the rate of 2 to 30 grams square meter of surface area and the adhesive may be a natural or synthetic resinous material a vegetable gum a soluble starch or starch ether or other suitable material it may be preferably to incorporate into the adhesive coating other ingredients such as for example surface active agents to improve the water absorption properties of the adhesive coating and fungicides to inhibit mould growth the process according to the invention may be used in the preparation of sheet materials having the most variegated effects thus for example two or more applications of a kicker composition may be made to different areas of the surface of the sheet after the treatment with a solvent conventional pigments may be employed in addition to the metallic ink in the different kicker compositions which moreover may contain differing concentrations of kicker after expansion of such a sheet a product is formed in which a variety of degrees of expansion have been obtained giving a product having a pleasing decorative effect in order that the invention may be well understood the production of a sheet material according to one.