The Long Arch

[HoGo]

I contacted LOC year or so ago with this issue and after month or two they sent me the correct pic but didn't put the correct one into their online library, yet.

Here is the correct one, BTW. Looks like it has quite smooth arch withoout flat area in the middle.

[HoGo]

Here is pic of the three violins exhibited by Vuillaume. One of the oldest photos of Messiah (center) and du Diable (right). The arching of du DIable is noticeably less flat than today (Biddulph pics) and also the scroll looks completely different from current scroll, at least to my eye. These things are somehow evolving over centuries...

[David Burgess]

24 minutes ago, HoGo said:

I contacted LOC year or so ago with this issue and after month or two they sent me the correct pic but didn't put the correct one into their online library, yet.

Here is the correct one, BTW. Looks like it has quite smooth arch withoout flat area in the middle.

Thanks, HoGo. It does look like it has a slightly flatter area in the middle, and bulging above and below that, but this can be readily explained by anyone with some decent mechanical acumen, which  you have demonstrated many times.

[HoGo]

One must be aware of the effect of modern lighting. The central arch generally gets a lot of light from side source and the typical neutral grey backdrop reflects in those parts while the parts shaded by the fingerboard and tailpiece will getmuch more contrast with background creating slight optical illusion that the center is more sunken than it really is. If you zoom into the Kreisler pic above you can see how the dents under bridge feet create a fake line of arch that is hard to distinguish on small screen without details.

I did some work on the old pic of Diable and recent one from Biddulph. The arch on the old pic is VERY close to perfect circle all along the curve visible (except slight dent in the bridge area and very slight bulge under fingerboard) the recent pic has a bit more bulge under fingerboard and flatter aree in front of bridge.

The curvature graph is not perfect - I used five points to define the curve of the arch in Photoshop which doesn't use curvature continuous splines so they create the kinks in the curvature graphs. The yellow line is perfect circle for comparison.

Also notice the distortion of the outer f-hole edge...

[Dr. Mark]

26 minutes ago, HoGo said:

One must be aware of the effect of modern lighting

Do you think those are the same violins?  Ignoring the neck, it's of course possible, as you suggest, that lighting effects - and also misalignment of the images - may account for the differences in the markings (e.g. in the upper photo, those in the C-bout appear more vertical than in the lower photo), but how did the mid-lower back become so linear?  How did the lower plate lose height under the lower corner?  And the bulge in the upper top plate seems pretty substantial considering that there's little apparent subsidence in the lower part of the plate to account for it.  I won't speculate since I have no skin in this game other than satisfying my curiosity.

[HoGo]

Yes, those bodies are the same (I believe the scroll is not the same, either changed at some time or heavily modified, but you need to look at original pictures and not my screenshot). You can see the scratch in the varnish of the upper bout that became black dirty one in the recent pic.

The flat part of back is actually cropped bottom of the picture (by me) as I wasn't really interested in back arches here.