Abstract: The invention relates to substrates bearing visible information that is secure against unauthorized copying obtained by applying information in the form of combinations of at least one emitting colorant and at least one reflecting colorant that are selected to exhibit similar or identical hues when viewed, with no cognizance being taken of fluorescence, and are applied in such a manner that their color fields touch, wherein the color loci of the two colorants correspond to one of the trichromatic colors yellow, magenta, or cyan and the reflecting colorant is an organic or inorganic pigment.

Abstract: The present invention relates to a process for preparing leather by (I) tanning a pelt with (a) an aldehyde, or (b) a bisulphite-blocked polyisocyanate; (II) optionally, retanning the pelt with (a) a polyaspartic acid, a salt of a polyaspartic acid, a polyaspartic acid anhydride, or a mixture thereof, and/or (b) a polyaspartamide; (III) dressing the resultant product by (a) bottoming the product with a polyurethane and one or more natural bottoming assistants, and (b) applying a polyurethane and/or polyesteramide finish; and (IV) optionally, aftertreating the resultant dressed leather with a leather preservative.