MODERN TRENDS IN THE ASSESSMENT OF SHAMPOOS 637 VISCOSITY BEHAVIOUR OF ,•/4 DILUTIONS 30'0 20'0 4•./. C D• 57'cDc I'f. C Doe TL40STRAIG HT Figure 3 VISCOSITY BEHAVIOUR OF I/8 DILUTIONS 25.0 27. C DE S'/.C D E 20.0 ß TL405TRAIGHT• • •7. C DE Figure 4

638 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS REFERENCES (1) J. Soc. Cosmetic Chemists 3 216 (1952). (2) W. W. Myddleton J. Soc. Cosmetic Chemists 4 150 (1953). (3) K. R. Dutton and W. B. Reinisch Soap Perfumery • Cosmetics 31 44 {1958). (4) G.E.New J. Soc. Cosmetic Chemists 11 390 (1960). (5) G.E.New in A. W. Middleton, Ed. Cosmetic Science 196oe 257 {1963) (Pergamon Press, London). Introduction by the lecturer The method which we adopted does not do away with the necessity of shampoo evaluation by salon or panel testing. It is possible to detect differences in shampoos using this home assessment technique which it is extremely difficult to confirm in the salon, and I do not think we ought to lose sight of the fact that what cannot be seen in the salon probably cannot be detected by a customer washing his or her own hair. The method proposed needs great attention it is essentially a method of technique and to obtain reasonable reproducibility of results it is essential that all operations must be checked and the techniques involved must be completely reproducible. The time taken for beating up the shampoo is important, and the temperature of the lather produced is also important during the estimation of viscosity. As long as the times and temperatures are strictly adhered to, fairly good reproducibility can be obtained, and we find that these tests are saving us a considerable amount'of time particularly where we are trying to evaluate a considerable number of shampoos we find that this method enables us to decide whether or not any particular formula- tion is worth checking in the salon. The use of a reference standard is of importance, and we selected tri- ethanolamine lauryl sulphate. Each batch of soil appears to have slightly different properties, and it is therefore essential that each new batch pre- pared should be checked against a standard of some kind. DISCUSSION MR. L. DEADMAN: Tests for foam characteristics get more and more complicated, yet some acceptable method of screening shampoos, at least for their major characteristic of lathering, would be of great value in order to check whether they are worth further testing in the salon. Have you tried the very simple method of just using a standard volume of shampoo, say 0.3 ml to wash the hands ? Obviously the lathering property of a shampoo is felt mostly by the hands. In our laboratory we find that the hand washing test gives the best correlation to actual use that we have been able to devise. Many different formulations can be tested in the course of just a few minutes. It is, however, essential, that the hands must be thoroughly