You are correct. Black ink absorbs all wavelengths, so it shatters easily. Colors are picky. Red ink absorbs green light (532nm wavelength) – that's fairly easy. Blue and green ink absorb red light (694nm or 755nm) – harder, but possible with the right laser (a Ruby or Alex laser). Yellow ink is the devil. Yellow reflects yellow light, so it's very hard to target. Some yellows can be faded, but often they remain as a faint stain. Also, pastel colors (light pinks, lavenders) often contain titanium dioxide (white), which can turn dark grey or black when lasered (called 'paradoxical darkening'). That darkening is usually removable, but it takes extra sessions. The bottom line: you need a clinic with multiple lasers (PicoSure for blue/green, and a Q-switched Nd:YAG for black/red). Do not go to a place that has only one laser. Ask specifically: 'Do you have a 532nm for red and a 755nm for blue/green?'