The discussion turned into some interesting dispute related with technological aspects of copying.
I was thinking about this, how one can get indistinguishable copy. The problem is that many methods
discusse d above have limitations because the physical properties involved posess
smoothing properties.
The latter are difficult to circumvent, to reduce the
smoothing. However, a technologies are evolving.
E.g., casting is constrained (between other factors) by the surface tension. Its impact can be diminished
using centrifuges and so on. Another physical constraint is a wave lenth of the light but it also can be overrun
using beams of elementary particles. Now I am far from this stuff but I remember that already at early 90 were technology
to make chips using electronic beams.
Such a technology should be extremely expensive and it is hard to imagine that it will have a practical use
to make
fakes even a very expensive
fakes. I would say that chemical sinking also is too expensive to produce
exclusive copies of the most popular 3rd century coins. I am always suspicious that
good copies of
cheap coins are produced somehow, but using other technology, maybe, a powder metallurgy.
Richard, since you are in the Lab, you can know more about this. You even mentioned somewhere that your colleagues,
using advance methods, could proved that some large bronzes you cannot condemn otherwise, are
fakes.
I was very impressed by that statement showing that the problem of "smart"
forgeries does exist.