Fading/discoloration or oxidation? I started Q-switch laser sessions 3 years ago (Photo)

The brownish or tan discoloration you're noticing during your Q-switch laser tattoo removal sessions is a common concern and can be attributed to several factors:

Ink Composition and Oxidation:

Tattoo inks can contain a variety of pigments and metals that may react differently under laser treatment. While you mentioned not using white ink, other colors, especially those with metallic bases, can oxidize and change color when exposed to laser energy. This is particularly true for inks containing iron oxide, which can turn a rusty brown or orangey-tan.
Ink Smudging:

The fading process can sometimes cause the appearance of smudging, where the ink particles are broken down but not completely removed, leading to a temporary discoloration. This can result in a mix of gray and tan hues as the ink disperses and is absorbed by the body.
Skin Reaction:

The laser process can also cause temporary changes in skin pigmentation, especially in individuals with darker skin tones. This is due to the laser's interaction with melanin in the skin, which can cause hyperpigmentation or hypopigmentation.
Lighting and Perception:

The appearance of the discoloration changing between orangey-tan and gray depending on the light could be due to how light reflects off the treated area, affecting how the colors are perceived.
Recommendations:

Consult with Your Practitioner: It's important to discuss these changes with your current laser technician or dermatologist. They can evaluate the discoloration and adjust treatment parameters if necessary.
Patch Testing: If you're concerned about further oxidation, ask about performing a small patch test to observe how your skin and the ink react to the laser.
Patience and Monitoring: The tattoo removal process can take multiple sessions, and changes in appearance are common. Keep monitoring the skin's reaction and communicate any concerns with your provider.
Overall, the discoloration you're experiencing is not uncommon, but close consultation with your practitioner will help ensure the best possible outcome for your tattoo removal journey.