Fit of the Langmuir-model (Eq. (10)) to the mix-, S- and sat-ranges of the corrected hook curve (see Figure 7). The lower panel illustrates the relation between the coordinate axes and intrinsic probe characteristics: The respective fraction of specifically hybridized PM-probes (Eq. (45)), their S/N-ratio (Eq. (46)) and occupancy (Eq. (43)). The arrows indicate the 50%-conditions at which the PM-probes on the average become equally hybridized with specific and non-specific transcripts (xPM, S = 0.5) and at which 50% of the oligomers of the PM-probe spots become occupied (ΘPM = 0.5). The third arrow points to the probes with a 100fold excess of specific hybridization.