Abstract: An article includes at least one surface with a visual feature included thereon and a plurality of elements with at least a portion of the elements being of selected optical states in accordance with a predetermined code, so that the visual feature is encoded with information. The article further includes a security feature which incorporates a security code with the security feature being formed so that the security code is random, and with the information encoded into the visual feature of the article, including a code derived from the security feature and correspondence to the security code.

Abstract: A substrate, such as a document of value, carries a design feature (F), which includes an array of repeating patterns with the patterns exhibiting discrete differences in one or more visual characteristics, for example, shape, color or optical responses, according to a predetermined pattern. The differences are, preferably, indiscernible to the unaided eye, but can be discriminated by an optical reading machine. In an alternatively preferred embodiment, the visual characteristics of each pattern represent 8- or 16-bit information.

Abstract: A substrate, such as a document of value, carries a design feature (F) which comprises an array of repeating patterns, the patterns exhibiting discrete differences in one or more visual characteristics (e.g. shape or colour or optical responses) according to a predetermined pattern. The differences are preferably indiscernible to the unaided eye but can be discriminated by an optical reading machine. In alternative embodiments, the visual characteristics of each pattern represent 8-or 16-bit information.

Abstract: An optical data storage disc having a first component disc formed over one side with a pattern of indentations defining digital data, the indented side of the first component disc being provided with a reflective coating, and a second component disc being bonded to the indented side of the first component disc. The second component disc carries a surface relief pattern having continuous variations in depth over a range of depths, and defining a holographic, or other optically variable, image.

Abstract: An optical data storage disc (e.g. a compact disc) carries a digital recording and also carries a holographic image. The holographic recording occupies an area separate from the area occupied by the digital recording, for example the holographic recording may be positioned in an annular area encircling the central area occupied by the digital recording.