The Depth of Cure for UV Gels
At NSI, we use a scientific method of evaluating how well a gel will cure under a UV lamp at a given length of time. This is called determining the “depth of cure.”
In the nail industry, depth of cure of a gel is a method of measuring whether gel enhancements of varying thicknesses are cured completely or just on the surface. If a gel is just cured on the surface, then the inside might be soft, uncured gel – leaving a potential for overexposure. This is why understanding depth of cure is so important.
Transparent and semi-transparent gels will typically cure completely in 2 – 3 minutes at any thickness. Therefore, determining depth of cure is not vital.
Super bright whites and highly pigmented deep rich colors contain more Titanium Dioxide (which makes them opaque). It’s harder for UV energy from a lamp to pass completely through these gels, especially if the gel is applied too thick. The whiter a gel is, or the more intense a color is, the greater the possibility that the UV energy is blocked. This is always why it is important to use clear tips when applying these types the gels. The clear tip allows UV energy penetrate from the bottom of the enhancement as it bounces off the deck of the lamp.
To determine the depth of cure for NSI gels, we use a special tool called a caliper. A caliper is a device used to measure the distance between two symmetrically opposing sides. The tips of the caliper are adjusted to fit across the points to be measured. In this case, we measure in units called millimeters. The chart below show the maximum thickness that some of our gels can be applied and still achieve a complete cure.
Here are some of our results:
Yes = Full cure at that depth
No= Not fully cured at that depth
# = Depth at which gel did cure
Product: | <0.5mm | 0.5mm | 1.0mm | 1.5mm |
| Balance Soft White Tip | Yes | Yes | Yes | Yes |
| Balance Soft White Sculptor | Yes | Yes | No | No |
| Balance X-Treme White | 0.25 | No | No | No |
| Balance Brush On French White | 0.25 | No | No | No |
| Balance Radiant White Sculptor | Yes | Yes | Yes | Yes |
| Balance Body Builder Bright White | Yes | Yes | No | No |
To give you a point of reference:
1.5mm is the same thickness as a US quarter
1.0mm is the same thickness as a US dime
0.5mm is the same thickness as an Elation Clear Tip
These gels were all tested with a 2 minute exposure in a Ultra Pro Full Hand Lamp, one that contains 4- 9 watt bulbs.
What does this mean to you, the nail technician? Just be cognizant of how you are applying white and heavily-pigmented gels. Rather than applying them really thick, try doing multiple layers and curing in between. This will ensure a complete cure and prevent overexposure.