Mark, this is really very interesting. I downloaded your image and opened it in Photoshop, attached a Curves layer in Screen mode so I could really see what's going on, and at 100% differences are hardly detectable - my eyes and my display - both very good dare I see, but perhaps not as good as yours' - that we'll never likely know! :-).
OK, I tried to do the same thing (open the 100% image, add a Curves layer in Screen mode). I see the same jagged/toothy edges, only now they're more pronounced because the Curves layer brightens the image. I can't comment on your eyes, but my eyes see the jaggies. And they're obvious.
Then I magnified the image to 200%, and indeed, at that magnification, the degree of edge pixellation is greater in the SF8 image than in the SF6 image. Of course anything magnified beyond 200% (which is one screen pixel per one image pixel) is bound to show some pixellation, so all that matters here is the relative appearance between the two application versions.
Agreed. I included the 300% shots to show the relative difference (and to prove that there is
a difference, even though the effect is exaggerated).
As to what's causing it, I can't say. BUT, what you see at these kind of magnifications is NOT necessarily what you will see in a print - in fact hardly ever. I recommend that you print both versions at your standard print settings and just examine the photos at normal viewing distance, and let us know what you find.
Done. And I've attached two scans of the resulting print (300 ppi and 800 ppi).
My conclusions: The effect is
less noticeable in a print than onscreen. In fact, the average viewer who knew nothing of this experiment probably would not notice any differences. But, to my eyes, the scan lines in the original SF 8 scan create a toothier/jagged roof line in the print. In the scans of the print (especially the 800 ppi scan), you can see that, where light and dark areas meet, small light and dark spikes intrude into each others' space, just as in the direct Kodachrome scan I posted earlier.
Ultimately, I still think SF 8 is not producing quality scans. (Or to be more accurate, it's producing flawed scans compared to SF 6.6; other than my jagged line problem, the quality is great.) I recently asked Lasersoft to help troubleshoot the problem again. They still couldn't reproduce the problem. But interestingly, in his most recent email, the support manager told me, "One of our developers is currently working on improvements for the Nikon scanners. He will look out for anything possibly causing this effect." I won't be holding my breath, but perhaps they will figure this out. But, to be honest, until they restore multi-scanning to SF 8, I seriously doubt this will be fixed.