Hi Kutter - No, it's not just you! I can understand what it says in the manual and in Charles' detailed tutorial, but unfortunately that understanding still doesn't translate into any intuitive feel as to what effect any particular filter/function is going to have. The manual tells me quite a bit of what I would need to know in order to write a programming routine to process a filter, but precious little to help in visualising their effect. I have resigned myself to the trial-and-error approach with the uncertain hope that some underlying principles will eventually be absorbed by osmosis.