Measuring Techniques: Start, Arch, and Tail Points with Consistent Angles

Concept: Three Primary Points Built from Consistent Angle Lines

This measuring method locates the start, arch, and tail points by projecting straight lines from the nostril to specific eye landmarks. The key is repeatability: the same anchor points, the same line direction, and the same contact/pressure on both sides of the face.

You will use three standard angle lines:

• Start point line: nostril → inner canthus (inner corner of the eye)
• Arch point line: nostril → outer iris (outer edge of the colored part of the eye, with the client looking straight ahead)
• Tail point line: nostril → outer canthus (outer corner of the eye)

Each line is a guide for where the point should land on the brow area. You will mark where the line intersects the brow’s natural growth zone, then verify it with a secondary check before committing to shaping decisions.

Workflow: Map the Three Points with Standard Angle Lines

Setup for accuracy (before making any marks)

• Client seated upright, head neutral (not tilted), eyes looking straight forward.
• Stand directly in front of the client so your viewing angle does not skew the line.
• Decide your nostril anchor: use the outer edge of the nostril wing consistently (same edge for all three lines and both sides).

Step 1 — Start point (nostril → inner canthus)

1. Anchor your string/ruler at the outer edge of the nostril wing on the side you are mapping.
2. Rotate the string/ruler so it passes through the inner canthus (inner eye corner).
3. Extend the line upward to the brow area. Where it intersects the brow growth zone is your start point candidate.
4. Make a small, precise mark (a dot or short tick) at the intersection.

Practical note: The start point is usually the most sensitive to tiny angle changes. Keep the tool straight and avoid “floating” it above the skin (details below).

Step 2 — Arch point (nostril → outer iris)

1. Keep the same nostril anchor (outer edge of nostril wing).
2. Ask the client to look straight ahead (not up or to the side).
3. Align the string/ruler from the nostril anchor through the outer edge of the iris (colored part of the eye).
4. Where the line intersects the brow growth zone is your arch point candidate.
5. Mark it lightly.

Tip for clarity: If the iris edge is hard to judge, have the client blink once and relax; then align to the visible outer iris boundary while the gaze is forward.

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Step 3 — Tail point (nostril → outer canthus)

1. Maintain the same nostril anchor.
2. Align the string/ruler from the nostril anchor through the outer canthus (outer eye corner).
3. Where the line meets the brow growth zone is your tail point candidate.
4. Mark it lightly.

Important: The tail point should not be forced beyond the natural brow growth just because the angle line extends farther. The line indicates a boundary; the brow still needs to look believable on that face.

How to Hold Mapping String or a Ruler So Lines Stay Straight and Repeatable

Mapping string technique (two-point tension)

• Anchor point: Place the string end precisely on the chosen nostril edge. Use a fingertip to hold it steady without sliding.
• Tension: Pull the string taut so it forms a straight line (no sag). A slack string creates a curved line and shifts your mark.
• Skin contact: Keep the string touching the skin lightly along its path. If it lifts off the face, the line becomes a “chord” in the air and changes the intersection point.
• Marking: Mark at the brow intersection while maintaining tension. If you release tension first, the line can drift.

Ruler technique (flat plane control)

• Edge placement: Use the ruler’s straight edge aligned from nostril anchor to the eye landmark.
• Contact: Keep the ruler edge lightly against the skin (do not press hard; pressure can distort soft tissue).
• Eye-level check: Before marking, confirm the ruler is truly passing through the intended eye landmark from your viewpoint (stand centered, not off to the side).

Repeatability habit: “Anchor–Aim–Touch–Mark”

Use the same micro-sequence for every line:

Anchor at nostril edge → Aim through eye landmark → Ensure light skin contact → Mark intersection

Secondary Checks: Verify Each Point Before You Trust It

Angle lines are powerful, but each point should be validated with a quick secondary check to prevent over-extended or under-placed marks.

Start point verification

• Tear duct proximity check: The start point should generally sit near the vertical zone above the tear duct/inner corner area, not drifting too far toward the nose bridge.
• Natural hair density check: Confirm there is realistic hair support at the start. If the line places the start in a sparse/no-growth area, keep the mark as a boundary but plan a softer start rather than a hard, boxed front.

Arch point verification

• Peak plausibility check: The arch point should land where the brow can naturally lift without creating a “surprised” look. If the mark is very high relative to the client’s natural brow, re-check your iris alignment and head position.
• Growth direction check: Look at hair direction through the mid-brow. The arch typically aligns with a subtle change in hair direction and thickness. If your mark sits where the brow is clearly flat and uniform, re-measure.

Tail point verification

• Natural brow growth boundary: The tail point should not extend far beyond where hairs naturally taper. If the line lands past the growth zone, keep the tail within believable density.
• Droop prevention check: Ensure the tail point does not sit noticeably lower than the start point on the same brow (unless the client’s natural brow clearly does). A tail that drops too low can create a tired expression.

Common Angle Errors and How to Avoid Them

Mini-Protocol: Right Side, Left Side, Then Cross-Check to the Midline

1) Map the right brow (three points)

• Start line: nostril → inner canthus → mark start candidate
• Arch line: nostril → outer iris → mark arch candidate
• Tail line: nostril → outer canthus → mark tail candidate
• Run secondary checks for start/arch/tail and adjust marks if needed

2) Map the left brow (three points)

• Repeat the exact same nostril anchor choice and holding method
• Mark start, arch, tail candidates
• Run secondary checks and adjust

3) Cross-check both brows against the midline before refining

• Visually confirm both start points sit at comparable distances from the facial midline (avoid one start creeping inward).
• Compare arch points: they should appear level and similarly placed relative to each eye when the head is neutral.
• Compare tail points: check that one tail is not significantly longer or lower unless the client’s natural growth strongly dictates it.
• If something looks off, re-measure the specific line (do not “eyeball-correct” without rechecking the angle).