John Dugdale's work comes to mind regarding this topic. His exhibits of cyanotypes are wonderful but there are no non image areas of the print shown when hung and they are very effective. Arentz is another.
When I contact print sheet film, for some series I like to show the entire rebate surrounded by a DMAX border - but no brush or coating marks. I have seen some printers worry and fret over making their brush marks look artistic to the point they forget about the actual image. Weird!