It should be emphasized once more that, in this case, the sensitivity of the liquid-penetrant testing, as a
rule, will not be determined. It is quite possible that cracks of smaller sizes than those available on the specimens
can be brought out using these materials according to the standard procedure of flaw detection. In the
case of a favorable result, this check solely confirms that these materials work properly; i.e., they are able
to reveal small cracks of a predetermined size. Only in some specific cases can the size of a crack on a specimen
coincide with the threshold sensitivity of the testing.