Iridescent colors with LOS

I have been reading more about LOS and how using salt and ammonia to
bring out the iridescent colors of gold, pink, purples, blues etc…
So my question is what is reacting with what to make these colors
And what are the compounds that are being formed?

Laurie K

My understanding is that the colors result from the varying
micromolecular thicknesses of LOS oxide building up on the metal and
the way light then refracts through it. That’s why one always gets
the same progression of colors: straw yellow, yellow, gold, pink,
vermillion, purple, blue, cobalt, gray. If one wants to stop the
color progression at a particular point, you have to stop the
build-up of LOS Oxide. Usually I do this by dipping my silver for no
more than 2 seconds in the liver, then dipping into ice water (slows
the chemical reaction down so I can look at it), then 2 seconds dip
in the LOS again. Then ice water, etc. When it’s the color I like, I
rinse in CLEAN ice water, then very gently pat dry.I have not yet
found a satisfactory way to seal the surface of the metal so that
the colors become permanent. I have tried waxes (including
Rennaisance Wax), which just dull the colors, clear acrylics, which
do the same, and several more exotic liquid applications such as
Agate Lacquer (nitro cellulose), all to no avail. My guess is that
these all affect the refractive index of the surface of the
metal/oxide and mess up the refraction angles, so the colors go
muddy, which is the normal result. So if anyone has figured out a
really good way to preserve these gorgeous colors I’d like to learn
about your technique and process.By the way, in addition to adding a
few drops of ammonia to your LOS solution, try this for really strong
colors: Mix your solution, not with warm water, but your morning cup
of black coffee. Yup!

Denny Turner