image height. cut from the side of the image to the other side.
the quarter, one third, one half, two thirds and three quarters taper is the area of which the image is smaller than the wide end.
one quarter: the image is 1/4 smaller than the total length of the bead.
for example total bead height: 1", image height 3/4".
one third: the image is 1/3 smaller than the total length of the bead.
for example: total bead height: 1", image height: 2/3".
one half: the image is 1/2 smaller than the total length of the bead.
for example: total bead height: 1", image height: 1/2".
two thirds: the image is 2/3 smaller than the total length 