Table 3.

Error budget for a single 3 μm center distance measurement, using CDP

Category	Error source	Error contribution (μm)
		Systematic	Random
On-axis magnification	Stage micrometer calibration	0.0068
	Film measuring machine calibration	0.0001
	Film readout, emulsion shifts, and magnification scatter (5 exposures)	0.0053
	Image distortion uncertainty	0.0020
		0.0089
Center distance measurement	Film readout and emulsion shifts		0.017
	Magnification scatter		0.008
	Image distortion-worst case		0.025
	Sphere flattening on contact		0.002
	Non-sphericity		0.030
	Subtotals	0.0089	0.043
Finite sample size (N = 4600)	Diameter distribution width		0.095
	Totals	0.0089	0.104

^aUncertainty in $\overline{D}/0.0089+0.104/\sqrt{4600}=0.011$ μm. Measured $\overline{D}$ (after correction, see Sec. 4.1.2): 2.977 μm.