It just occurred to me. Most papers laced with FWA are coated on one side only. The back side of the paper is uncoated and has no brighteners. Graeme, might it be practical to manually incorporate a reading of the back side of a paper for the purposes of FWA measurement? I'm thinking something like an instruction at the beginning or end of reading a chart to flip the paper over and read any clean spot. Only done with an appropriate command-line switch, of course. Cheers, b&