When explaining tattoo removal, one of the first questions many people ask is, “How many sessions will it take to remove it?”

 

To answer that, there is something we need to look at first.

 

We need to check what colors the tattoo contains, and which laser wavelength can best target each of those colors.

 

This is because tattoo removal is not a treatment that erases the surface of the skin like rubbing with an eraser.

 

Instead, it is a process of breaking down ink particles located in the dermal layer of the skin with laser energy, and then allowing the body to gradually clear those smaller fragments.

That is why the important point in tattoo removal is not simply saying, “A pico laser is good.”

 

What matters much more is that different colors respond better to different wavelengths, depending on whether the tattoo is black, red, yellow, blue, or another color.

 

In this article, I would like to explain why tattoo removal strategies need to change depending on tattoo color, based on a study that shows this concept in a more detailed way :)

 

The study referenced here is a 2018 preliminary study by Choi et al. published in PLoS ONE.

 

This study compared 532 nm nanosecond, 532 nm picosecond, 755 nm picosecond, 1064 nm nanosecond, and 1064 nm picosecond lasers for multicolored tattoo removal in a Hartley guinea pig model.

 

In other words, this was not simply a study comparing “pico versus nano.”

 

It also compared how wavelength and pulse duration can produce different responses depending on tattoo color.

 

Tattoo removal is ultimately a treatment that breaks ink according to color

 

 

Tattoo ink is not just sitting on the surface of the skin.

 

It exists as particles embedded inside the dermis.

 

Laser energy is delivered to these ink particles in an extremely short period of time, breaking them into smaller fragments.

 

After that, immune cells such as macrophages gradually process and clear those fragments.

 

Simply put, tattoo removal is not really about “burning the tattoo away.”

 

It is closer to breaking large ink particles into pieces small enough for the body to clean up over time.

 

That is why it becomes important to understand which pigment absorbs which wavelength more effectively.

 

For example, black ink tends to respond relatively well to several wavelengths, while red, orange, and yellow pigments are often approached mainly with 532 nm wavelengths.

 

Blue and green pigments are often better targeted with 755 nm wavelengths.

 

Of course, in real clinical practice, the result can vary depending on ink composition, depth, density, and whether the tattoo has been covered up before, so this should not be simplified into a fixed formula.

 

 

Still, the main principle is that different colors respond better to different wavelengths.

 

If you look at the image above, the response differs quite a lot depending on the color

 

In the first attached image, orange-toned, yellow-toned, and blue-toned tattoos are shown from left to right.

 

The vertical rows show 532 nm Nano, 532 nm Pico, 755 nm Pico, 1064 nm Nano, and 1064 nm Pico.

 

Each section is arranged in the order of Pre, Post, and Week 3, allowing us to compare the immediate post-treatment response and the change after three weeks.

 

What makes this figure helpful is that it does not simply show whether the tattoo “faded well.”

 

It shows which color faded better with which wavelength, and in which combinations the skin reaction appeared rougher or less favorable.

 

Looking first at the orange-toned pigment, the change appears more noticeable with the 532 nm wavelength group.

 

Especially with the 532 nm picosecond laser, the tattoo color seems to fade further over time after treatment, while the response appears relatively weaker with the 755 nm picosecond and 1064 nm wavelength groups.

 

This can be understood in relation to the principle that orange-toned pigment tends to absorb 532 nm wavelength more effectively.

 

The yellow-toned pigment in the middle is even more interesting.

 

Yellow is a color that patients often assume will be easy to remove because it looks light.

 

In reality, however, it can be more difficult than expected.

 

In this image, the 532 nm wavelength group shows some response, but the changes with other wavelengths appear more limited or less consistent.

 

In other words, yellow is not necessarily an easy color just because it looks pale.

 

It is a color that may respond only when the wavelength is selected appropriately.

 

Looking at the blue-toned pigment, the 755 nm picosecond laser appears relatively more favorable.

 

On the other hand, the 532 nm wavelength group appears less efficient for blue tattoos than expected.

 

This also matches the reason why 755 nm wavelengths are often considered important for blue and green tattoo pigments in clinical practice.

 

So this first image shows very intuitively that tattoo removal is not a treatment where every color can be pushed through with one laser.

 

It is a treatment that requires matching the wavelength to the color.

 

The second electron microscopy image shows how yellow ink particles are fragmented

 

The second attached image shows yellow pigment under electron microscopy.

 

The lower left shows the normal control, and the other panels show 532-N, 532-P, 755-N with no data, 755-P, 1064-N, and 1064-P

This image looks one step deeper than the visible color change on the surface.

 

It shows how ink particles actually exist inside cells, and how they become fragmented after laser treatment, at a microscopic level.

 

Simply put, it shows traces of tattoo ink being broken into smaller pieces inside the skin.

This is important because tattoo removal effects should not be understood only as “the tattoo looks lighter from the outside.”

 

This figure helps show what kind of changes the laser can actually create at the pigment-particle level.

 

Yellow is clinically one of the more difficult colors, and microscopic images like this help explain more convincingly that even within the same yellow pigment, fragmentation may occur better with certain wavelengths and less effectively under other conditions.

 

The key point of this study is that pico is not everything. Wavelength matters

 

During tattoo removal consultations, I often hear the question, “Isn’t the pico laser the best?”

 

Of course, picosecond lasers can help break tattoo particles into smaller fragments because of their shorter pulse duration.

 

However, the name “pico” alone does not mean that every color will be removed well.

 

The key message from this study is rather that selecting the right wavelength for the color is very important.

 

If the wavelength does not match the pigment, even a picosecond laser may show limited response.

 

On the other hand, when an appropriate wavelength is selected, a better removal effect can be expected.

 

In the study, 532 nm was an important wavelength for red, orange, and yellow-toned pigments, while the 755 nm picosecond laser showed a favorable response for blue-toned pigment.

 

For black tattoos, the 1064 nm picosecond laser was reported as the most effective.

 

These findings ultimately lead to the conclusion that we need to classify the tattoo colors first and then select the wavelength accordingly.

 

However, in clinical practice, yellow, apricot, and skin-colored pigments need to be approached more carefully

There is one more important point to add.

 

Although the study showed responses in yellow pigment, in actual clinical practice, yellow, apricot, skin-colored tattoos, and cosmetic tattoos still need to be approached with caution.

 

That is because these pigments may have inconsistent compositions, and paradoxical darkening may occur after laser treatment, meaning the color can become darker instead of lighter.

 

From the patient’s perspective, it is easy to think, “It looks light, so it should be easy to remove.”

 

But in reality, these colors often belong to the more difficult category.

 

Especially cover-up tattoos using skin-colored pigment, cosmetic tattoos containing apricot-toned ink, and tattoos close to the mucosa need to be evaluated even more carefully.

 

So tattoo removal should not be understood as “lighter colors are easier.”

 

In some cases, the lighter the color appears, the more strategic the approach needs to be.

 

To summarize, tattoo removal is a treatment that starts by separating colors

 

Tattoo removal becomes clearer when we understand that the first step is to identify the tattoo colors and then select wavelengths that can properly target each color.

 

In the end, what matters in tattoo removal is not trying to remove everything strongly in one session.

 

It is about distinguishing the colors, assessing the depth, adjusting the wavelength according to the remaining pigment, and allowing the skin enough time to recover.

 

In other words, when it comes to tattoo removal, the more important question is not simply “Is the laser good?”

It is whether there is a strategy that matches the colors of your tattoo :)

 

This was Director Won Dae-han.

 

Thank you for reading.

 

Choi MS, Seo HS, Kim JG, Choe SJ, Park BC, Kim MH, Hong SP.
Effects of picosecond laser on the multi-colored tattoo removal using Hartley guinea pig: A preliminary study.
PLoS ONE. 2018;13(9). DOI: 10.1371/journal.pone.0203370.

 

※ This article is intended to provide general medical information.
Actual suitability for tattoo removal, laser wavelength, number of sessions, and treatment intervals may vary depending on tattoo color, depth, location, skin type, and previous treatment history.
In particular, yellow, apricot, and skin-colored tattoos may respond differently than expected, so the treatment plan should be determined after consultation.