E. P. Osmolovskaya’s scientific contributions

Putting l = 1 m, we obtain A = 2.5 mm for dma x = 0.5 mm, and A = 250 mm for dmi n = 0.005 mm. Measurement may be effected by using the diffraction interval A with a constant screen position (l = const), i.e., by an absolute method, or by determining the distance from the object to the screen for a constant diffraction interval, matching a standard value, i.e., by a relative method. In the first case the error will be mainly determined by the random error committed in measuring the diffraction interval, in the second case by the random errors committed in measuring the distance to the screen and making the diffraction interval coincide with the standard.

Strips with a surface finish of ? 12 and over may be measured with a total error of the order of ±0.0003 mm, and for a surface finish of under ? 12 with one of the order of ±0.001 mm.