Newton black film

https://doi.org/10.1351/goldbook.N04136
In
soap
films, two types of
equilibrium film
are often observed, sometimes successively in the same system: one characterized by thicknesses of the order of 7 nm or more which varies significantly with minor changes in composition such as
ionic strength
, and the other having a lesser thickness relatively independent of such changes. When a distinction is needed, the former are designated as
common black films
, and the latter as Newton black films. The current use of first or secondary for the
common black film
and of second, primary or Perrin's for the Newton black film is discouraged.
Source:
PAC, 1972, 31, 577. (Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry) on page 614 [Terms] [Paper]