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Irridescent florentine

Hi, Is any one familiar with achieving an “irridescent” effect from
a florentined finish ? My customer insists that the ring she’s having
us re-make had such a finish … My memory say’s I’ve seen this
effect somewhere in the past but I can only guess at the
technique/tooling necissary to achieve the effect . Any help?

Mark Clodius

The only irridescence I’ve ever seen in florentine is when the
oxidation forming in the recessed areas tends to give a shimmering
effect rather than an obvious darkening. Caused, I suppose, by the
fact that the very fine recesses are tarnishing, but the higher
ridges are constantly being ‘polished’ by wear.Jim

Clodius, I’m sure the following link will be useful :

Have fun doing it

    Hi, Is any one familiar with achieving an "irridescent" 
effect from a florentined finish ? Mark Clodius 

Hi Mark; Apart from the possibility she’s referring to the Guilloche
enameling technique, I’ve seen an irridescense, or sorts, in the form
of tarnish as it occurs on flourentine finishes. After a while, the
interesting effect becomes plain old brown. Florentine finish a
scrap of gold, dip it in chlorine bleach and leave it around for a
while and see if you get that effect I’m talking about. You could
check that with the customer, and also find an example of Guilloche
to show her.

David L. Huffman

Great link.Thanks AvA. I would add this. I usually add a third cut
that runs at a 45 degree angle to the other two. This gives a much
more iridescent look to the Florentine. This might give the look the
custome is after instead of the traditional cross cut. Just one of
the ways that I do things differently. Frank Goss

Mark, I was just working on a piece and finishing it with sandpaper
while letting the ring spin with the force from the split sanding
mandrel in the foredom. I also create this finish by holding the
ring in my hand against a belt sander and letting the ring spin with
the force of the belt sander. This creates a sparkling sort of finsh
that has a certain irridescents. This may be what your customer is
talking about. I usually use 220 or 360 grit corrundum paper. You
might try it on a ring and show it to the customer. Might be what
they are looking for, might be something new you can use.This
technique works best on bands as they rotate more even. Frank Goss

Hi , My theory is that an extremly fine network of parallel lines
will form a diffracting surface , giving the irridescent effect . We
certainly do "normal " florentining here , my inclination is that
this is not a tarnish effect but is one of extreme precision and
high line count , not perhaps achievable with out machine tooling .
Does any one here have experience along such areas?

Thank You
Mark Clodius

Hi Mark, I’m thinking that if you do the florentine and then cross it
at a very slight angle, (rather than a right angle) it gives kind of
a moire effect—that sort of seems to shimmer—that might be
it… Cindy

Dear Artists and Creative Persons, I recently made a "simulated=
cd or lp record for a charm bracelet. The final product showed an
irridescence. This the item was a 14k gold disk with a hole in the
center, chucked on the flex shaft and “surfaced” gently with a
carbide scribe point. The lines were close enough together to
produce the diffraction effect and a true irridescense.

The spacing is what does it, I believe. Most florentine gravers are
much too coarse for this effect. The lines must be tight enough to
diffract light and break up the colors. To try to produce the
effect on another surface shape would be very difficult. The
resulting effect on the charm was most rewarding, mimicking the look
of a CDdisc. I have seen the “pseudo” effect from tarnish=
florentine work. The irridescence is there but of a different sort,
from actual color and not from diffraction and scattering of the

God Bless. TomDart. @Sp.T

   The spacing is what does it, I believe. Most florentine gravers
are much too coarse for this effec 

True enough. The irridescent you refer to is essentially, a
reflective diffraction grating. That means spacing on the same order
as the wavelength of visible light.

While florentine gravers don’t produce cuts that close together,
cutting edges can be either intentionally, or accidentally, capable
of producing grooved surfaces like this. The grooves don’t have to
be deep, after all. One can buy, so I’m told, diamond tipped
cutting tools for engine turning machines, or diamond facetting
machines, or similar equipment, where the cutting edges are grooved at
the appropriate intervals that the cut surfaces are then
irridescent. And such tools may well also be used to produce the mold
surfaces used to make some of the various plastic products with
irridescent/diffraction grating surfaces, since most of those are not
cut directly into the plastic, but rather just metal tools pressed
into the plastic. I’m thinking, for example, of the various foil
stickers and decorative wrapping papers that use such finishes…

And what I’m wondering, though I’ve not tried it, is whether it
might be possible for a jeweler to produce a graver that might, at
least slightly, produce such a finish. I’m thinking of perhaps a
carbide graver (so it will last a little bit) sharpened on a diamond
facetting disk using and appropriate grit size to produce the sorts
of groove sizes and spacing that might give somewhat of a diffraction
effect. obviously, since the grooves from an abrasive are random,
the spacing wouldn’t be uniform, so the effect wouldn’t be all that
great, but one might get it somewhere close, perhaps… Worth a try
maybe, for someone who’s already got the facetting equipment…

Peter Rowe

I recently found a new new manufacture of silver guilloche (engine turning) disks in US:

I ordered couple of pieces for test, they look good.