A flexible character-indentable plastics embossing tape (11) is backed by and bonded to a lead strip not more than 0.025 inches (ie. approximately 0.65 millimetres) thick, to form a tape suitable for identifying radiographs. The lead strip (13) is itself backed by a relatively thin and flimsy plastics or fabric strip (15) which, when removed, allows the lead (and hence the lead-plastic tape as a whole) to be pressure-bonded to the surface to be radiographed. A conventional tape-embossing gun is used to indent the desired characters in succession, and in order, into the lead-backed tape, without necessarily severing the lead; and then the backing strip (15) is peeled away to expose the layer (14) of adhesive which pressure-bonds the indented tape to the object to be radiographed. X-rays incident on the embossed tape will cause the raised characters (a) to show up dark on the subsequently-developed film, whilst the raised side areas (b) will show up white. Each character will thus stand out on the developed film.