344 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Test method The test was carried out in Africa on a panel of 40 male volunteers. Most of the subjects were chosen because they had jobs which caused them to spend a considerable amount of their time out of doors, since it was sus- pected that strong sunlight might be playing some part in the efficiency of the bleach creams. The groups were matched on the basis of the reflectance values of the skin on the outside of the forearm. Each group used only one of the previously mentioned products during the whole test period. Application of the creams These creams were applied to four test sites on each person, namely the outside upper forearm and the outside of the wrist on each arm, by means of a cardboard template. In this way the central portion of the outside fore- arm could act as the control site for each arm. It was also hoped that the subjects would agree to apply the appropriate skin bleach cream product to their faces, but only a few were willing to do so. The cardboard template was located on the outside of the forearm by placing one end on the head of the ulna bone of the wrist. The presence of the template caused some difficulty during the rubbing in of the creams and it was found that the operators applying the cream became so adept in judging the area of ap- plication that the template was only used to locate the application area and then removed when the cream was rubbed in. The creams were applied twice daily during the working week (5 days) by skilled operators (the few subjects who agreed to use the cream on their faces were allowed to apply it themselves, but only to their faces). Approximately 0.25 g of cream was applied to each test site on each occasion. Since the test lasted 8 weeks there was a total of 10 (subjects) x 40 (days) x 2 (applications) x 4 (test sites)--3200 applications of each cream during this test. Examination The subjects were examined before the test began using a variety of subjective and objective evaluation techniques. In addition the panel mem- bers were examined by a consultant dermatologist to ensure that they were

EVALUATION OF SKIN BLEACH CREAMS 345 suitable for the test (i.e. had no existing diseases or history of allergy/sensi- tization), and also during the test in order to detect any signs of primary irritation that might develop. Evaluation techniques Both subjective and objective methods for assessing the degree of skin lightening were used in this test. To avoid any bias, conscious or uncon- scious, in the subjective evaluations, it was decided to carry out the subjec- tive evaluations before the objective measurements were made. In addition the panel members were examined in a completely random order which was dictated by their availability. The evaluation techniques employed were the following. Grey scale wedge assessment The shade intensity of colours of the skin on both the test sites and con- trol sites of the forearms were matched with the same set of numbered photographic standards as that used in the guinea-pig tests (Fig. 1). Visual assessment The colours of the treatment sites were visually compared with the control site on each arm and the degree of lightening was assessed using the following simple numerical scoring system: •core Degree of Lightening 0 No difference + 1 Slightly lighter +2 Noticeably lighter +3 Markedly lighter Photographic assessment Photographs were taken of the forearms and faces of all subjects initially and of the forearm on each examination. Final photographs were taken of the faces of a few subjects who agreed to apply the creams to their faces. The photographs of the forearms were taken with a 'Startec' clinical camera fitted with a flash attachment and the forearms were photographed against a standard grey background. The background was used as an addi- tional control when micro-densitometer traces were made of the test and