Before choosing the type of curl for your client, you must know that the angle of natural lashes will make a huge impact on the end result of the design.

✅ There are three types of natural lash angles: straight, downwards, and upwards.

For example, look at the image below. B curl lash is used for both eyes but you can see the difference in the end result.

On the first model, the natural lash is pointing downwards. As a result, you do not see any lifting or open eye effect.

On the second model, the natural lash is pointing upwards. As a result, you can see the B curl lashes give enough of a lift, thus creating the effect of a more open eye.

So, don’t forget that the expression of the curl changes depends on the angle of the natural lashes. If your eyelash extension supplies cabinet is full of just popular curls like C and D curls, you will be limited in offering a truly customized look.

To make our job a little more challenging, natural eyelashes on one eye don’t necessarily have the same angle as on the other eye. You may see many clients have a mix of different angled lashes on one eye, like in the example below.

Your goal here is to make the end result as even as possible. So, mix up the appropriate curls according to the angle of the natural lashes.

Not all curls will have the same retention or longevity. The curlier the lash, the shorter the retention, because there is less of the natural lash for the base of the extension to attach to. So, it is essential to choose the right combination of curl and thickness of the extensions according to your client's natural lash.

If you have trouble attaching the curly false eyelashes, we highly recommend trying our EZ-curl lashes.

📌 Subtle curls (I, J, B curls)

✅ I curl lashes
A lesser known curl, I curl extensions are almost straight in shape, and they can be used for male clients who want to enhance the thickness of their lash but don’t necessarily want to have them curled.

✅ J curl lashes
J curl is the most natural looking curl. These are especially suitable for clients who have stick straight lashes pointing straight or upward. If you apply a J curl to a downward-looking natural lash, it will make the eyes look smaller and heavy.

✅ B curl lashes
B curl will give the straight natural lashes a bit more lift than a J curl. B curl lashes have a bit more curl than J curls, but they are still an excellent option for clients with straight lashes that point straight or upward. Also, the B curl is an excellent option for inner corner lashes. B curl lashes offer a soft curl, a standard for a naturally enhanced lash appearance with excellent retention.

📌 Dramatic curls (C, D, U curls)

✅ C curl lashes
C curl is intended for clients with a slight curl in their natural lash and will create an open eye effect. C curl is one of the most popular curls worldwide. If C curl is used for clients with slightly downward angled lashes, it will give a satisfying lash lift. If used for clients with close-to-horizontal angle lashes, it will provide a fabulous doll eye effect.However, for clients with heavily downward-angled lashes, we recommend using D curl instead.

✅ D curl lashes (also known as CC curl)
D curl is very similar to C curl, just curlier. They are especially effective for clients with downward-angled lashes who want a show-stopping look. These lashes will brighten and widen the eye and give a noticeable curled effect.
Because of its dramatic upward curl, if used for clients with upward-angle natural lashes or with heavily hooded eyelids, the extensions may prick the client's eyelids. For that reason, D curl is more suitable for clients with downward-angle natural lashes.
It's one of the curlier curls, and if not applied correctly, retention may not be as great as the straight curls, but it adds drama and opens the eye more, making it excellent for downward-angled natural lashes.

✅ U curl lashes (also known as DD Curl)
U curl is the curliest lash extension. They are suitable for clients with downward-angled lashes who want the most dramatic doll-like eyelashes. These lashes will give a noticeable curled effect.
Just like D curl, because of its dramatic upward curl, if used for clients with upward-angle natural lashes or heavily hooded eyelids, the extensions may prick the client's eyelids. For that reason, U curl is more suitable for clients with downward-angle natural lashes.

📌 Lift-up curls (M, L, L+ curls)

✅ M curl lashes
M curl gives the opposite effect to what J curl does. Its shape being with a small surface for the flat base and a dramatic curl upwards, M curl is designed to lift the appearance of downward-angled natural lashes. Because of the dramatic upward angle, you will be able to give a lash lift and create a wide-eye effect. M curl is not recommended for clients with hooded eyelids or upward angled natural lashes.

✅ L curl and L+ curl lashes
L and L+ curls are essentially C or D curls with a flat base. Because of the flat base, you will be able to give your client the ultimate eyelid lift. L and L+ curl are developed to provide a wide-eye effect to the clients with hooded eyelids, deep-set eyes, and older clients with droopy eyelids. L+ is slightly curlier than L. These are the most visually rewarding lash extensions. However, because of their long flat base, if used on downward-angle lashes, they will appear to be heavy and unflattering.

📌 Better-bonding curls (EZ curls)

✅ EZ curl lashes
The base curl of EZ Lash is straighter than the normal extension lashes, and as a result, EZ lash provides a more adhesive area for extensions and allows for a much easier extension experience for beginner lash artists. Thanks to its wider adhesive area, EZ curl lashes also provide better retention. However, because of their long flat base, if used on downward-angle lashes, they will appear to be heavy and unflattering.

Did you know all lash extension curls that currently exist in the market, with the exception of J and C curl, were actually invented by BL Lashes? Because of this, we have the broadest range of curls to offer. We believe having a variety of curls in your salon will enable you to serve your clients by tailoring to their eye shape and desired style.

Eyelashes extensions are made of PBT. The material itself doesn't expire, but over time, the lash curls can lose their shape. To prevent the curls from relaxing, keep it in a cool, dry place away from direct sunlight or humidity.

Choosing the right diameter of the eyelash extensions for a client is critical. When deciding the thickness, you should not only consider the design aspect but, more importantly, the condition of your client's natural lashes.

Some thicker extensions (above 0.20, for example) can be too heavy for some clients' natural lashes. A wrong choice could cause poor retention and premature falling off of the extensions.

Generally, the natural eyelashes of Asians are thinner than those of other ethnicities. Also, you’ll notice that with clients over the age of 50 their eyelashes are thinner than your younger clients.

For these clients, it is recommended to use lash extensions of diameter between 0.10-0.15mm (for Classic), whereas other clients with stronger natural lashes can take 0.15-0.20mm (for Classic). 

However, regardless of the ethnicity or age of your client, you should always take a good look at the client's natural lashes and decide what thickness is suitable for them.

If you are unsure about the thickness of your client’s natural lash, compare with your lash extensions (which are labeled with the thickness) to determine the rough diameter of the natural lash. From there, it’ll be easier to decide how much weight the natural lash can handle.

One topic many lash technicians find confusing is how to calculate the correct number of extensions for the Volume technique. The ‘D’ in 2D, 3D, 5D, ~20D is short for Dimension, and it is used to describe how many strands were used for one volume fan.

Calculating the correct volume fan size comes from understanding the thickness x weight relation of the eyelashes extension.

For example, considering 0.15mm of eyelash extension (weight about 0.00017g) to be a standard thickness to be applied on one natural eyelash, ultra-thin lashes like 0.03mm lash extensions  (weight 1/20 of 0.15 lash extension) can be safely used as 20D.

Need help? We have detailed instructions on How to calculate volume lash size weight.

📌 Lash Thickness for Volume Lash Application

✅ 0.03mm and 0.05mm lashes
The popular thickness for Mega Volume style for 2D-6D.

✅ 0.06mm and 0.07mm lashes
The popular thickness for Russian Volume for 5D.

📌 Lash Thickness for Volume & Classic Lash Application

✅ 0.10mm diameter lashes
This thickness can be used for Volume 2D-3D (depending on the natural lash’s strength) or as Classic 1D on thinner, very fine natural lashes.

📌 Lash Thickness for Classic Lash Application

✅ 0.12mm lashes
Used on thinner lashes (Classic) or for a softer, wispier look and feel.

✅ 0.15mm lashes
This is the most popular, average lash thickness, which creates a naturally thicker look (Classic).

✅ 0.18mm lashes
This lash extension thickness creates a slightly bolder look than the 0.15mm lash.

✅ 0.20mm lashes
The second most popular thickness for the classic extension. This lash extension thickness creates a natural mascara look. We recommend using it only on thick and healthy natural lash.

📌 Very Thick Eyelash Extensions

✅ 0.25mm lashes
This extension creates a glamorous look, though it may be too heavy for most people's lashes.

✅ 0.30mm lashes
For healthy, strong, thick natural lashes. Creates an extreme look, although it might be too heavy for most people's lashes.

BL lash extensions produce extension lashes with lengths from 5mm-20mm. The most popular extension length is around 11mm or 12mm.

Generally speaking, shorter extensions of 5-9mm are used for inner corners or under eyelash extensions, and 9-13mm extensions are used for the majority of the set. Some artists mix longer lengths from 14mm or longer lashes to create a Hybrid eyelash extension.

Naturally, many customers want the longest lashes, but it is essential to keep in mind that the individual client's lash condition should determine the length of the extension.

It is your responsibility to guide your client if the lashes are too long for their natural lash, as they may cause premature falling out of the extensions.

Choose slightly longer lashes for clients with hooded eyelids or droopy eyelids. Their lashes tend to 'hide' under the eyelids when the eyes are open.

When using the curlier false lashes like D and U curls, remember when the curl is strong, the length of the extension will appear shorter. So, choose the lash length according to the curl you are using.