One thing to note is that blade exposure isn’t the distance from the top-cap to the edge of the blade. Blade exposure is measured while looking at the razor from the side.
The picture you shared shows “cap span” as it’s called in the picture below. The “shave plane” is the reference used to determine blade exposure.
This example picture has a slightly positive blade exposure. If a razor designer wanted to decrease the blade exposure they could do a few things – make the safety bar stick out further, make the top cap thicker, make the top cap stick out more (like shown in the photo you shared). Any one of these changes alone doesn’t determine the geometry of the head though, since there are two surfaces in play (the top cap and the safety bar).
One thing to note is that blade exposure isn’t the distance from the top-cap to the edge of the blade. Blade exposure is measured while looking at the razor from the side.
The picture you shared shows “cap span” as it’s called in the picture below. The “shave plane” is the reference used to determine blade exposure.
This example picture has a slightly positive blade exposure. If a razor designer wanted to decrease the blade exposure they could do a few things – make the safety bar stick out further, make the top cap thicker, make the top cap stick out more (like shown in the photo you shared). Any one of these changes alone doesn’t determine the geometry of the head though, since there are two surfaces in play (the top cap and the safety bar).
Thanks walden!