many thanks for the encouraging comments guys.
yep, Keith and ebbtide - you've caught me

- I've found that using a flatbed scanner quicker and easier than using even my digicam - especially for small object like knives. Even scanning at a humble lowly 150dpi can yield well focussed high definition and detailed images.
With obviously the reservation that mirror polished blades can cause some difficulties (as they do with conventional cameras). Whereas satin and matte bead-blast finishes are reproduced really well
This was the first time I've seen this rainbow effect - I actually (perhaps perversely) find it quite attractive - although it is not, strictly speaking, a true respresentation of the blade.
I think/guess the rainbow effect might have something to do with the blades being aligned with the scanning sensors (eg: parallel or at right-angles) causing an optical effect.
Whereas the diagonal scans don't seem to have quite as pronounced rainbowing - like this other "diagonal" pic of the stag drop point -
A little while back I wrote something on flatbed scanners -
some general flatbed Scanners advice
If you look carefully at the other diagonal pic of the stag drop-point - perhaps you can just see the sheath's formed contour is of the actual stag handle - these sheaths appear to be individually formed for each of the knives - and not mass produced from a single template knife (that's why on the reverse side of the sheath on the horizontal pic of the stag drop-point there's a number at the lower end of the belt loop - which is the serial # of the knife itself etched on the lower end of the tang near the guard.)