the following dissolved ingredients at the indicated aim dry coverages these elements were prepared the same as control 1 except that the barrier layer was various metals as shown in table 1 which were deposited by vacuum deposition prior to vacuum deposition the substrate was coated with a subbing layer of poly acrylonitrile co vinylidene chloride co acrylic acid 14 79 7 wt ratio 0 05 g m 2 the amount of metal barrier layer was measured by uv optical density as reported in table 1 the elements were then coated with the same image layer as in control 1 the image layer was adjusted to make the total uv image layer plus barrier layer density fall approximately in the range between 3 5 and about 4 2 the above recording elements were imaged with a diode laser imaging device as described in u s pat no 5 387 496 the laser beam had a wavelength of 830 nm and a nominal power output of 450 mwatts per channel at the end of the optical fiber the table lists uv transmission density recorded on an x rite u00ae densitometer model 310 x rite co the intermediate uv density or plateau and the exposure required to reach the plateau are reported where some recording elements exhibit more than one plateau only the one associated with the undisturbed metal barrier layer is reported the speed of the recording elements as measured by the exposure needed to reach d min were acceptable for the.