I had a lovely plot (see below) that showed that showed that Beer's law doesn't do all that bad of a job at predicting the ink trajectory (and the hook) of a magenta ink. The plot shows how close the match is in a*b*. Erik pointed out that I didn't show what is going on with L*. It could be that Beer's law works well in a*b*, but really messes up when it comes to L*.
The magenta hook, real and estimated
So, I had a look at this same data from a few other perspectives. Here is what the data looks like in the L*a* plane.