Graduation's final shape is affected by several factors.
1. Elevation angle
Graduation is created by elevating the hair to 90 degrees or less from the horizontal. If it is 90 degrees of elevation the hair is all combed straight back from its natural fall position with all the hairs in the strand being parallel to each other and to the floor.
If the hair is elevated less than 90 degrees, the hairs in the strand are still parallel but the ends of the hair are lower than before. Lowering the hair half way between the horizontal and the floor will give a 45 degree elevation.
Lowering the hair from 90 degrees of elevation will lower the placement of the line of graduation. The longer lengths which make the top of the graduation will start lower because the head shape will begin to slope away from the head sooner as the graduation goes up from the hairline in the nape.
2. Cutting angle
Perpendicular Cutting Angle
Finger angle or cutting angle also moves the placement of the line of graduation.
As an example think of a section elevated to 90 degrees. All the hair here is combed straight back so that all the strands are parallel to each other and to the floor.
If the cutting angle is perpendicular to the floor, the length of the hairs in the section will increase at the top of the section as the head form curves away from the cutting line. This increase in length is what forms the boundary at the top of the graduation.
45 Degree Cutting Angle
Cutting the 90 degree horizontal section with a finger angle or cutting angle of 45 degrees across this strand is also a common practice. This angle has the scissors pointing in at the neck with the handles pulled away from the head. The effect is to make the hairs longer at the top of the section. This means that the top of the sections increase more rapidly in length compared to cutting with a line that is perpendicular or straight up and down. With the increasing length in the hair as you work up the section, the top of the graduation is reached sooner. This places the line of graduation lower on the head form compared to the perpendicular cutting angle.
Concave Cutting Angle
Cutting the 90 degree horizontal section with a cutting angle that points away from the nape with the handles of the scissors closer to the head creates a concave section. This has the top of the section shorter at top. This means that the boundary of the top of the graduation is not formed until very near the top of the head where the head dramatically curves away from the cutting line. This moves the top of the graduation further up the head shape. This graduated shape is flatter and tends to slope in the direction of the concave cutting. Weight is created under this shape by the extensive length cut into the bottom of the shape.
3. Sideways Over Direction
Over directing the sections to either side will give an inconsistent line of graduation. Over directing can be checked for prior to cutting.
The first check is to look at your body position and see if the section is in front of you. This will give you a chance to see if the hair in the section is being held over its section on the head. This is done by seeing that the hair is within the parts on each side of the section. If the section is in front of you, you have a good view of the parts and this makes it more likely you will keep it there during combing and cutting. Keeping the sections both in front of you and over the natural fall section of the hair means the body position shifts as different sections are cut.
4. Up Down Over Direction
Over directing the sections up and down will also give an inconsistent line of graduation.
The flow in the sections is determined in the first section cut. Once this has been done, a piece of a previously cut section should be incorporated in the new section to check that the flow of the hair is consistent. This is done by seeing that the hair is parallel to the flow in the previously cut section.
Over directing the section up moves from graduation to layering and this removes weight from the graduation line. The definition of the line becomes mushy or curved.