> The relatively fixed or arbitrary interpolation > between the sampling points ignores any knowledge about the > typical, reasonable or desirable behaviour of the device between > sampling points. In addition there are issues with trying > to get reasonable extrapolated results, something that > often crops up in scanner profiling. Actually I always wondered why are the interpolation algorithms not parametric, adjustable per a device model for better precision... Even without a previous device model; for example after reading a chart of 4096 patches, instead of building a table with 4096 gridpoints and a simplistic interpolation between them, use the "in-between" patches for tuning the interpolation algorithm via some parameters, and then build a table with fewer gridpoints (or maybe even the same 4096) but additional data to drive the interpolation. A gridpoint might have, for example, one more byte defining a 'sphere of influence'. Or maybe a vector defining an ellipse of influence centered on the gridpoint. Or maybe a vector plus a linear offset value so that the ellipse is not centered. Etc etc. ; Maybe a single byte defining a 'density of space' at the gridpoint. I'm no matematician, but I guess there are ways to go beyond blind interpolation.... -- Roberto