Abstract: A printing compound suitable for recording unique surface characteristics of an object such as a person's finger, palm or foot, tire tread or shoe sole, on a porous medium such as paper, is composed of (1) a composition, e.g., printer's ink, capable of delineating such surface characteristics when transferred to the porous medium by itself or in conjunction with a separate reagent and (2) a sufficient amount of water dispersable nonionic surfactant to render the composition substantially soluble in water without adversely affecting the ability of the composition to delineate the surface characteristics when transferred to the porous medium.

Abstract: A method of developing latent fingerprints involves the preparation of an 8-quinolinol complex by mixing a solution of 8-hydroxyquinoline or a derivative with a complexing reagent such as a metal salt. The solution is then applied to a porous substrate, such as paper, containing the latent fingerprint where the soluble complex is adsorbed onto the surface of the latent print and precipitates thereon. The unadsorbed solution is then removed from the substrate allowing the precipitate to highlight the latent image. The choice of the complexing reagent will determine the color of the precipitate and whether or not it is flourescent.

Abstract: A method of recording fingerprints in which a solution of monohydrogen or dihydrogen ester having an AAV of about 9 or more is applied to a person's fingerprint area with the area then pressed onto a thermosensitive substrate.

Abstract: A self contained three sheet fingerprint applicator and recording substrate utilizes a base sheet (10) adapted to be fixed to a suitable surface, such as a package, for receiving the fingerprint, an intermediate sheet (14) with a removable section containing an ink pad (14a) infused with an ink or inkless regent compatible with the development of a fingerprint when transferred to the base sheet (10) by a person's fingerprint area and a top sheet (16) with a removable section covering the ink pad.

Abstract: A nonstaining ink (or inkless) fingerprint composition and applicator comprises two nonpermeable foil strips, made of Mylar, for example, having the same width with one strip being slightly longer than the other. A thin layer or coating of an inkless (or nonstaining) fingerprint composition is sandwiched between the superimposed foil strips leaving a small border including a small area at the end of the strips free of the composition. The inkless composition which includes a color former and may or may not include a developer is in a semisolid state and room temperature and in a liquid state at about 110° F. and above.

Abstract: An inkless fingerprint compound includes a solvent, a color former, such as a transistion metal salt, compatible with the solvent and a developer such as hydroxiquinoline and derivatives, the developer capable of reacting with the color former to form a colorant product, preferably black in color. A sufficient amount of a chelating agent, such as a carboxylic acid, is added to the solution to prevent the color former and developer from reacting while in solution to form the colorant product while permitting such reaction when the solution is applied to the fingerprint area of the person to be fingerprinted and deposited onto a paper substrate.