What substance in Silly Putty picks up newsprint?
Why does it do that?
A Google search turned up a few sites, although I did not see the specific answer to your question. My guess would be that it is simply adhesive enough to remove the top layer of ink from the paper. You can do the same thing by lightly moistening a paper towel or looseleaf paper, pressing it on and pulling it straight off. You can do it by picking up a paper with sweaty hands; the ink comes right off onto your palm. (It comes off on dry hands, as well, but it requires mild rubbing, so that it generally smears.)