From the Wikipedia page on skin - http://en.wikipedia.org/wiki/Epidermis_%28skin%29 - "The outermost layer of epidermis consists of 25 to 30 layers of dead cells."

If you are removing any cells past this point, you will experience irritation. If you go "under the skin" as you put it, regardless of blade sharpness, you will experience the worst razor burn imaginable. If there is any way there is to cut a hair below the skin line, it is by pulling the hair out and then cutting it. Fortunately, you will pull the hair out just a little bit if your razor is at the lower end of the sharpness scale, and your second stroke over this area will cut the pulled hair (sort of like what Gillette advertised with their two-blade razors).

If you have a really sharp edge like the feather, it won't pull the hair out on that first stroke, and the second stroke will do nothing but slice off the upper strata of the epidermis along with some more hair, leading to razor burn. Thus, a blade at the level of feather sharpness will actually shave less close than a blade at a lower level of sharpness for a given level of skin irritation.

But it will be better than a blade that is less sharp with only one stroke on any given area of skin.

If you want to prove this for yourself, do the following experiment:

Using your favorite razor on one side of your face and a feather on the other, shave such that on any given area of skin, you take exactly one stroke with the razor. With or across or against the grain is your choice, but you need to do the same thing on both sides of your face. In some shaving videos you'll see people doing the same area of skin multiple times in the same pass - basically scraping the same spot again and again before moving to a new spot. Don't do this, especially not on the feather side .

Which razor gives you the closer shave?


Quote Originally Posted by poona View Post
BBS smoothness is about cutting the hairs under the skin surely? As theyre pulled by the cut, they slice under the outer dermis. A lighter
touch wouldnt achieve this so I think a balance between sharpness and touch needs to be sought in order to get the ultimate shave.