Beauty & Laser training

Short answer: choose length, curl and thickness from the natural lash first, the eye shape second and the client's wishes third. Most lash damage and poor retention come from going too long, too thick or too curly for the natural lash.

Always complete a full consultation and patch test before choosing any product.

Step 1: Assess the client first

Before picking up a tray, look closely at the natural lashes and the eye, and note these on the consultation card.

Step 2: Choose the length

Choose an extension 2–3mm longer than the natural lash it sits on. Going much longer adds leverage and weight at the root, which can cause early shedding or traction damage to the follicle.

Rules for length:

• Measure each zone separately. Inner-corner lashes are shorter than the centre, so they need shorter extensions.
• Use your longest lengths only where the natural lashes are long and strong.
• Never apply a longer extension to a short, fine or baby lash. It will droop, twist or fall early.
• For a first set or a nervous client, stay at the +2mm end of the range.

Lash mapping

A lash map splits the eye into zones from inner to outer corner and sets a length for each. The map creates the style.

Step 3: Choose the curl

Choose the curl from the direction the natural lash grows and the shape of the eye. A straight or downward lash needs more curl to look lifted; an upturned lash needs less, or it will curl back towards the brow.

Curl and retention: curlier extensions have a shorter flat base touching the natural lash. Less contact means a weaker bond, so the more curl you use, the more important precise isolation and placement become.

Match curl to eye shape:

• Hooded eyes: B, L or a soft C, so the lashes clear the lid fold.
• Monolid eyes: L or CC to lift the lashes out from under the lid.
• Deep-set eyes: B or C; strong curls may touch the brow bone.
• Downturned eyes: L or C, with longer lengths at the arch (squirrel map) to lift the outer corner.
• Prominent or round eyes: J, B or C; strong curls exaggerate roundness.

Step 4: Choose the thickness (diameter)

Choose a diameter no thicker than the natural lash can comfortably support. For most classic sets, that means 0.10–0.15mm.

Weight rises with the square of the diameter, not in a straight line. At the same length, a 0.20mm lash is 16 times heavier than a 0.05mm lash, and a 0.15mm lash is more than twice as heavy as a 0.10mm lash. A small step up in thickness is a big step up in weight.

Rules for thickness:

• Fine or damaged natural lashes: 0.07–0.10mm, and keep the length short.
• Longer extensions need a finer diameter to keep the total weight safe.
• A volume fan should weigh about the same as one classic lash. A 3D fan of 0.07mm weighs roughly the same as one 0.12mm classic lash.
• If in doubt, go finer. A slightly lighter look is better than damaged natural lashes.

Step 5: Put it together

Work in this order every time: natural lash first, then eye shape, then the client's wishes. These examples show how the three choices combine.

Common mistakes

• Going longer than the natural lash can support, because the client asked for drama.
• Using one length all the way across instead of mapping by zone.
• Using a strong curl on hooded or deep-set eyes, so the lashes hit the lid or brow bone.
• Putting heavy diameters on fine or damaged lashes.
• Putting long extensions on short, fine inner-corner or baby lashes.
• Not checking the set with the eyes open. Always check symmetry and lift with the client sitting up and eyes open.

Student checklist before you start

• Consultation, contraindication check and patch test completed
• Natural lash length measured in each zone
• Natural lash thickness and health assessed
• Natural lash direction noted
• Eye shape identified
• Lifestyle (glasses, sleep position, sport) discussed
• Lash map drawn and agreed with the client
• Length, curl and diameter recorded on the client card for infills