FACIAL OILINESS AND DRYNESS 251 Emollient Softening Effect on Soap-Washed Skin Outline of Protocol 1. The entire face washed with soap and water ! ! I ! 2. "Equilibration" for 15 minutes 22C and 15% RH ! ! I 3. Baseline ("before"} measurements ! ! ! ! 4. Emollient Lotion Applied 1/2 face I I ! I 5. "After" measurements Figure 10. Protocol for assessing emollient effects on soap-washed skin. Emollient softening of soap-washed skin was tested, using the procedure outlined in Figure 10. The results are presented in Figure 11. Here, softening is indicated by negative changes in DSR, using the calculation just described. Once again, changes were more readily perceived on the cheeks than on the forehead, although a trend toward larger decreases at this (latter) site is apparent. SUMMARY AND CONLUSIONS Self-assessed oiliness varied two-fold on the face, with the rank order as forehead = nasal fold cheek. Friction meter readings also varied two-fold, with the rank order as cheek nasal fold -- forehead. Observed differences were therefore comparable in magnitude, but there was a reciprocal relationship between surface friction and perceived oiliness, consistent with prior work (1,3). Perceived oiliness was reduced by washing while surface friction increased. Thus, the changes were also reciprocally related. Applied to washed skin, some emollient products may leave a residue which does not reduce the frictional increase, but which nevertheless may be perceived as slightly more oily than soap-washed skin. The skin surface was found to be stiffer on the forehead than on the cheeks--about a two-fold difference, measured by GBE. This difference is probably due to the extent to

252 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS MUCH I SOFTER SLIGHTLY SOFTER EQUAL Perceived Stiffness, t vs c* Cheek Forehead 1 2 3 4 5 6 7 1 2 3 4 5 6 7 SUBJECT SUBJECT +IO0 +50 EQUAL 0 -50 DSR, Shift in Percent Difference between Treated & Control Sites Cheek Forehead miniriB n 1 2 3 4 5 6 7 1 2 3 4 5 6 7 SUBJECT SUBJECT *T and C are treatment and control respectively. *MUCH SOFTER means that the treatment side was much softer. *EQUAL means that they were equally stiff, etc. Figure 11. Emollient softening of soap and water washed skin. Shift is as defined in Figure 9. which the skin is stretched in situ rather than to a qualitative difference in the stratum corneum. GBE measurements on contralateral sites may be very different, even when subjects say the areas are "equal" in stiffness. This shows that there may be a certain amount of asymmetry on the face which subjects have come to perceive as normal. Not all lotions or creams alter the measured stiffness of the skin surface (GBE) nor the perception of stiffness by the subjects formulation comparisons therefore are possible without a significant "placebo" effect. Soap and water washing may stiffen the skin surface some 20-100% as measured by the