Abstract
A 24 h test described previously has been adopted as a standard test. By keeping the remainder of the prescribed conditions the same but increasing the test temperature to 60°C, the test period is shortened to at most two hours. A number of observations are reported on the use of the 24 h test and, for copper substrates only, a modification is suggested which facilitates counting pores at high density. The size of pores and their retention of trapped plating electrolyte are discussed.