Justification: There is no systematic data in the literature about the transmission of neutron resonance filters. Such information probably exists in various instrument-log-books, but it would serve the community well to have systematic comparative measurements. To do this we require a white neutron beam up to energies of ~1eV, for which ALF is well suited if we run with a de-phased nimonic chopper. We plan to measure 10 different filters, and anticipate setup and optimisation of the experimental configuration to take about 1 day, leaving 3 days to complete the transmission measurements.