The tattoo ink is gradually ingested by cells that wall it off and hold it in place. This process takes about a month to be completed , so treatment during that first month may be more effective as the pigment is freely dispersed in the skin and more susceptable to laser fragmentation. Doing 4 treatment sessions in a single day also increases the effectiveness of laser treatment as the laser reacts with the most superficial layer of ink ,but waiting 20-30 minutes between treatments allows progessively deeper laser penetration.