this is how you do it...just like with film, when you have to copy something with a surface texture, cross polarize it--use a copystand type setup with a camera, put polarizing screens in front of the lights, orient these in the same direction. set up your camera (film or digital) with a polarizing filter and turn that until the texture is knocked out.
works like a charm with old tweed type ektalure prints, old c-prints and all sorts of other stuff, especially silvered out old photos. you have to remember that in the old-days, the texture was often used as a device to thwart copying, back then, as now, the only way around it was to use polarizers on the lights & the lens.
hope this helps.