I have been asked to copy some old colourised family prints for a friend. The print has a stipple to it as per the attachment, which gives a pattern of dots in the image which shows up in the file. I shot it in light from a window, as I thought that it may do a better job than lights. It's about a 12"x16" print so I can't scan it fully on my V800. I tried on part of it and still get the stipple. I'm at a loss to know whether I can get my lights set up to minimise the dots.

All suggestions will be gratefully received.