The result of the pre-processing procedure is illustrated for the cell line SU-DHL-4. The circles represent absorbance measures for the particular concentration at which it is plotted, the triangles represent the un-treated controls, the plusses represent background absorbance measurements, and, finally, the crosses illustrate outliers. The figure is divided into eight panels, where Panels A, C, E, and G show the results for time t1 = 1 hour and Panels B, D, F, and H for time t2 = 49 hours. Panels A and B show the raw absorbance measures for the four replicated experiments. The effect of the colour correction is shown in Panels C and D. Panels E and F illustrate the result of the conventionally applied background correction. Finally, the result of the model-based pre-processing procedure is illustrated in Panels G and H.