Im not sure how to address plain ribs with damascus tubes. For me they tend to end up looking an unattractive scuffed-up gray, with brighter edges. At least for the top ribs, Ive considered applying more rusting solution to just that section for another pass or two. I suspect it would not work out that easily, and would probably cause problems with the finished achieved on the tubes.
On the other hand the ribs are entirely plain steel, and the etchant takes bluing off of the steel to expose the pattern on the tubes, then a lot of blue coming of the ribs in this case would be expected. I just don't think it looks nice.
