Abstract: A method of forming an image and a radiation-sensitive medium suitable for carrying an image is disclosed. The medium comprises a substrate having a surface structure comprising grooves with a depth of 20 to 100 nanometers. At or close to the surface structure there is a layer of radiation-responsive material which is such that irradiation of selected parts of the structure with radiation of a predetermined polarization causes radiation to be absorbed at the irradiated parts of the surface so that corresponding areas of the radiation-responsive layer are affected in a way which makes such areas distinguishable from the remaining, non-irradiated areas of the radiation-responsive layer. An image and/or data may be stored in such a medium in analogue, digital or pictorial form, or in a combination of any two or all three of these forms. The invention also provides primary and secondary pre-formed data carrying media, the secondary media being replicated from the primary media.

Abstract: A data storage medium is provided which is suitable for production or replication by moulding, casting, embossing or a similar process against a tool. The data storage medium has a surface or a surface region which is strongly absorbent of at least a predetermined band of wavelengths of electromagnetic radiation. The surface or surface region includes a layer of a material which undergoes a large volume change or degradation and has a regular, sinuous textured surface pattern which is free from undercutting. The textured surface pattern is coated with a thin film of platinum or a platinum alloy, the thickness of the overcoating preferably being such as to give no more than 10% transmission of incident radiation.A method of storing information on such a data storage medium is also disclosed. The data storage medium may be prepared in blank form for use as the consumer desires, or it may be pre-recorded in part or in entirety.