Sorry for getting in on this so late. Jens, one of the reasons I can see someone scratching an area more than "needed" is that as one hits metal, especially like gold or silver (or even brass) the metal expands horizontally. Precise lining of a border is nearly impossible for the old techniques (and even today) of inlay and koftgari. As it expands, you would want all of the precious metal to catch in as many grooves as possible and thus lessen the chance of comming out later. Also, these were done by hand and some impression is to be expected, so any metal that wondered slightly out of the original plan is covered by extra grooves just in case.
|