QTR-Quadtone RIP

Assuming that you use a spectrophotometer to measure the patches, bring your data (% black and L*a*b*) into Excel and plot each L, a, b, vs. % black.  Starting with the L vs. %K data plot, inspect for inconsistent points (anomolies)and delete them from the colum of L values.  Then add a 6th order polynomial trendline and check the box to show the trendline equation.  Use these coefficients to generate a "model" curve using the %K as "X" values.  Optionally, do the same for the "a" and "b" values.  Copy the "model" output values into the L*a*b values in a QTR-compatible text file, save it and drop this onto the "QTR-linearize" droplet.  Copy the linearized values into the curve description file and you should have (nearly) perfectly smooth curve(s).  The only problem I've seen with this method is that occasionally, if you have too high an ink density, the "model" curve may increase slightly at the highest %K values.  If this happens, just manually edit the last point or two to give slightly decresing L values.