RADIATION INDICATOR DEVICE

A radiation indicator device for use in indicating exposure to ultraviolet -B radiation. The device includes a radiation sensitive mixture which is selectively responsive to ultraviolet radiation having a wavelength substantially within or shorter than the range of wavelengths of ultraviolet-B radiation. The radiation sensitive mixture includes an organic halogen constituent capable of producing at leas t one acidic product upon exposure to ultraviolet radiation and an indicator constituent capable of producing a change in colour in response to a change in concentration of the acidic product. The radiation sensitive mixture has a first colour representing a relatively low concentration of the acidic product and has a second colour representing a relatively high concentration of the acidic product. The first colour is visually distinguishable from the second colour. The device may also include a graphic pattern interposed amongst the radiation sensitive mixture, which graphic pattern has a graphic pattern colour substantially identical to either the first colour or the second colour.