A laser does not see a drawing. It sees pigments that absorb certain wavelengths and reflect others. Two tattoos of the same size can therefore need very different work depending on the colours they contain.
The basic rule is simple: the more an ink absorbs the laser light, the more easily it breaks up. Black absorbs almost everything. Yellow reflects a large part of the visible spectrum. In between lies a whole range of responses, sometimes surprising.
Why colour changes everything
A tattoo removal laser emits a precise wavelength, in nanometres. The pigment has to absorb it in order to heat up, fracture and be cleared by the body. If the ink reflects that wavelength, the energy passes it by.
That is why a practitioner does not treat every colour with the same setting. The wavelength is chosen according to what is visible, and sometimes according to what is discovered over the sessions.
| Colour | Wavelength often used | Usual difficulty |
|---|---|---|
| Black, dark blue | 1064 nm | Low to medium |
| Blue, green | 694 nm or 755 nm | Medium to high |
| Red, orange, purple | 532 nm | Medium, with a risk of darkening |
| Yellow | 510 nm or 532 nm | High |
| White, beige, flesh | test first, often 532 nm | Very high, darkening possible |
This table gives an indicative order. The exact ink, its depth and your skin’s reaction matter as much as the visible colour.
Black and dark blue: the easiest
Black is the pigment that clears fastest in most cases. It absorbs all wavelengths, and 1064 nm penetrates deep enough into the dermis to reach the most buried particles. Dark blue and grey often follow the same path.
That does not mean black disappears in two sessions. A fine, old lettering can fade quickly. A dense black fill, laid down in several passes, can take much longer. Pigment density matters as much as colour.
Red and orange: often good, with traps
Red responds well to 532 nm. That is one reason red tattoos are often cited among the easiest after black. Orange and purple also respond to this wavelength, with more variability.
Two traps exist. First, some red inks contain iron oxides. Under the laser, ferric oxide can reduce to darker ferrous oxide: the red turns brown or black. Second, red is the colour that triggers the most allergic reactions. If the area is already irritated, swollen or itching, the skin should be examined before it is treated.
Green and light blue: the right wavelength
Green is one of the colours that resist. Green pigments absorb 1064 nm poorly, and a 694 nm or 755 nm laser is often needed. Alexandrite picosecond lasers are regularly used for these shades.
Light blue and turquoise can be capricious too. They sometimes contain pigments based on copper or cobalt, whose response varies. The good news: when the wavelength fits, green can respond very well. It simply asks for patience and sometimes a change of setting during treatment.
Yellow: the pigment that resists
Yellow is one of the hardest colours to remove. It reflects a large part of visible light, notably red and green, and therefore absorbs little of the energy of current lasers. Some yellow inks also contain titanium dioxide to make them brighter, which complicates the response further.
The result is unpredictable: a yellow may fade slowly, stay visible after several sessions, or barely move. In some cases the practitioner prefers not to push, to avoid damaging the skin. Better to know this before starting.
White and flesh tones: watch for darkening
White, beige, pale pink and flesh tones are the pigments that call for the most caution. They often contain titanium dioxide, sometimes zinc or iron oxides. The heat of the laser can alter these compounds and turn the area grey, brown or black.
This darkening is not systematic, but it is documented enough to justify a test on a small area. When it happens, it can be temporary or persistent, and several extra sessions are sometimes needed to fade it. Some practitioners then choose another technique, such as an ablative laser, so as not to target the metallic pigment directly.
Mixes, cover-ups and cosmetic inks
Tattoo artists mix inks to obtain a shade. A black may contain a touch of blue, a red may be lightened with white. A covered tattoo hides a first layer, sometimes of another colour. All of this makes prediction difficult.
Cosmetic pigments, used for microblading, permanent makeup on brows or lips, are a separate case. They often contain metallic oxides and change colour with time. A brow that looks black may hide a red or orange pigment that becomes visible after a few sessions. We cover this in detail in brow tattoo removal.
How to find out before starting
Three actions help you form a fair idea:
- photograph the tattoo in daylight, without a filter, to see the real colours;
- ask the tattoo artist, if possible, what ink was used;
- do a test on a small area, then wait 6 to 8 weeks before judging.
A test does not say everything, but it reveals the bad surprises: darkening, allergic reaction, weak response. It is particularly useful for white, yellow, red and cosmetic pigments.
Finally, do not judge a colour on the first session. Fading continues for several weeks, and it is sometimes at the third or fourth session that an ink really starts to respond. The total number of sessions remains a range, never a promise. To understand what makes that number vary, read how many sessions to plan.