Human figures

Hi! I´m going to make and send to the printer one of those figures made to actual heights and body shape, I don´t know if I explain myself :stuck_out_tongue: The picture is of a boy and I need to make it to his real height which is 120 cm, my question is what should I know to make it? dpi?? I got a nice high quality picture but still I have to scale up the image, any recommendations?? thanks!