When placing an image that is going to fill a frame, does it make any difference whether the frame has a fill of 'None' or a fill colour (or gradient for that matter)? I have always used 'None' as the fill. I have been advised that it's best practice to use PAPER or 0% of black as the RIP can get confused with a fill of 'None'. Does it make any difference? Does it make a difference to any trapping that may get applied?
I've used [None] for years unless I actually need a different fill. Quark used to have a problem with unfilled frames and grayscale or images not knocking out properly, but I've never had a problem with ID.
Anyone telling you that is someone you should not listen to since that person is living in the 1990s.