Will laser hair removal effect my tattoo? The tattoo is on my rear shoulder.
If you are going to try to treat that particular area for hair removal, then YES, your tattoo will be affected. You will receive a nasty burn, depending on which laser is being used and the tattoo will also be ruined! You cannot receive hair removal treatments on an area that is tattooed 
I have not seen any problem with treating the tattoos of my clients with electrolysis. I have a few guys who have come to clear out just the area of the tattoo so the art is more presentable.
One gentleman had a beautiful buxom bikini girl on his leg, however, before we cleared out the area of the tattoo, she looked like a wolf girl because of all the hair on HIS legs. We cleared out the whole thing, and the tattoo did not fade a bit.
I can not, however say that those results would be universal. Not everyone would be using the type of equipment that I use, and as with everything else, the skill of the practitioner and the vision equipment as well as the mobility of the salon chair for that matter, all come into play when evaluating the best possible result from any treatment proposal.
I wish you luck.
PS, I would have my sample treatments on some place other than my tattoo if I were you.