Roger Breton wrote: > I have not looked at your code but do you use a "fixed" correction or a > "dynamic" > correction in argyll FWA compensation? Sorry Roger, it's hard to answer such a question. Every reading is different, so by definition nothing is fixed. If you're imagining something like a static shift in b*, then no - far from it. It's a spectral correction model of the way the light interacts with the media, including the FWA response. Graeme Gill.