Have you ever wondered how laser tattoo removal works? We explain the science behind Q-switched laser technology and how it is used to remove tattoo ink. To understand this process, you first need to know how tattoos are created.
How tattoos are applied to the skin
Using a mechanised needle, a tattoo artist punctures the skin and injects ink into it. The needle repeatedly and rapidly pricks the skin, dragging the ink down into the dermis – the second layer of skin just below the epidermis. The ink in a professional tattoo is inserted more uniformly beneath the skin than in an amateur one, which is applied at varying depths. Why does the ink have to be placed in the dermis? Because the outer skin cells of the epidermis are continually dying and shedding; if it were applied into the epidermis the tattoo would disappear after a few weeks.
The skin is essentially wounded by these thousands of tiny needle pricks and the ink particles are immediately treated by the body’s immune system as a foreign object. The body’s inflammatory response begins: it sends special cells called microphages – a type of white blood cell – to the site of the tattoo to engulf the foreign ink particles and dispose of them via the lymphatic system. This engulfing and elimination of foreign objects is called phagocytosis. However, most of the tattoo ink particles engulfed by the microphages are too large to be expelled. These then remain ‘trapped’ in the dermis, and the ink stays visible forever. That’s why tattoos are permanent.
How laser tattoo removal works
Q-switched lasers are the industry standard for the non-invasive removal of tattoos. They work by firing very short pulses (quantified in nanoseconds or 1/1,000,000,000 of a second) of highly concentrated light energy at the tattoo through the skin. The tattoo pigment absorbs this energy and breaks down into tiny fragments. Because the Q-switched laser pulse is so short it is incredibly precise, and the surrounding tissue is not heated up. The shockwave created when the laser energy hits the tattoo pigment and shatters it is called the photomechanical effect. The fragmented particles of ink are then small enough for the skin’s immune system to absorb and are expelled initially via the bloodstream and then though the lymphatic system. The tattoo starts to fade over the subsequent days and weeks following treatment.
Laser treatment is safe and highly effective, but several treatments are needed for complete removal of a tattoo. Typically, laser treatment sessions are spaced at about 8 weeks apart. This is to give the body’s lymphatic system time to flush away the fragmented ink particles. The number of total sessions required to fully remove the tattoo depends on many factors and is not always straightforward to predict.
Different tattoo pigment colours absorb specific wavelengths of light on the spectrum. Consequently, different lasers are needed for different tattoo colours. Multi-coloured tattoos will therefore require treatment with two or more laser wavelengths. Black is the easiest pigment to remove because it absorbs all wavelengths, and can be treated by almost any laser.
These are the most common lasers used in tattoo removal, together with their wavelength in nanometres:-
- Q-switched Nd:YAG 1064nm. This is the most common laser in use in tattoo removal. It creates an invisible (infrared) light which is absorbed by all dark tattoo pigments, such as blacks, black-blues and dark greens.
- Q-switched Frequency-doubled Nd:YAG 532nm. This laser creates a green light which is absorbed by red and orange inks.
- Q-switched Ruby 694nm. This laser creates a red light which is used to target light greens and blues.
- Q-switched Alexandrite 755nm. This is the weakest of all Q-switched lasers. It creates a red light that is absorbed by darker colours like black, dark blue and dark green, but it is not able to treat reds and oranges.
- Q-switched lasers also have other important settings:-
Pulse duration. Measured in nanoseconds or picoseconds.
Spot size – the width of the laser beam. Larger spot sizes increase the penetration depth of the laser, better able to target deeper tattoo pigments; on the other hand, smaller spot sizes may be needed for more accurate targeting of smaller areas.
Fluence. Measured in Joules per square cm, this has to be set high enough to shatter the tattoo ink particles. The fluence is gradually increased as the treatments progress as deeper layers of ink are targeted and the tattoo fades.
There are dozens of different laser machines in use by tattoo removal clinics in Sydney. The majority of Q-switched lasers in tattoo removal clinics will have dual wavelength Nd:YAG 1064nm and Nd:YAG 532nm – the two most common.
Watch our explainer video
If you are trying to choose a suitable tattoo removal clinic, the laser machine being used is a very important factor. Avoid generic beauticians who are offering tattoo removal as an additional service. Their laser machines are likely to be cheap, Chinese-made tabletop devices that at best won’t remove your tattoo effectively, and at worst could leave you with scarring.
Also avoid IPL lasers. These are designed for hair removal only. They have a longer pulse length which creates heat and can burn or even scar the skin. IPL lasers should never be used for tattoo removal.
Give us a call at Fade to Blank
The best thing to do if you are considering laser tattoo removal treatment is to come in and talk to one of our experts on the process and its suitability for you. Having tattoo removed by laser is a safe and effective form of treatment.
We can provide you with a free no obligation quote. So give us a call today.