Table 1.

Preparation of McFarland turbidity standards and corresponding OD₆₀₀ value.

1% (wt/vol) BaCl2 (μL)a	1% (vol/vol) H2SO4 (μL)	%vol/vol of 1% BaCl2 in total volume	Corresponding OD600
0	3,000	0	0
10.89	2,989	0.363	0.1
21.78	2,978	0.726	0.2
32.67	2,967	1.089	0.3
43.56	2,956	1.452	0.4
54.45	2,945	1.815	0.5
65.34	2,934	2.178	0.6
76.23	2,923	2.541	0.7
87.12	2,912	2.904	0.8
98.01	2,901	3.267	0.9
108.9	2,891	3.63	1

^aThe indicated μL quantities are for the preparation of 3 mL of standards; the volumes can be scaled up or down accordingly.