glass is unique among all glass products. Dichroic glass exhibits a color
and reflective depth totally unlike that of traditional stained glass, in
that the colors actually change with the type and direction of the light
that illuminates it. It is perfect for use in jewelry work, as well as
scientific applications, many of which the private sector enjoys benefit.
But at the same time, it is rather complicated to manufacture.
Dichroic glass is
made by starting with clear glass as the base or substrate, and covering it
with multiple layers of metallic coatings, specifically oxides of titanium,
silicon and magnesium. A 300º, two chamber vacuum furnace is needed to
insure adherence of the metal materials, because the atmosphere
surrounding the glass must be pure to allow clean transference of the evaporants from the lower chamber to the glass sheet suspended above it in
the top chamber. A high-voltage electron beam is the conduit for this transference. The
glass is hung from a device that both rotates and revolves the glass at the same time,
similar in movement to the Earth's in its course around the sun, to insure an even
coating. In spite of the extreme care taken in the laboratory to make the coating even,
success can vary greatly from sheet to sheet in the finished product, which allows for
changes in color from place to place within the same sheet.
coated, the glass is covered with what acts as a filter or lens. Light absorbs into it, (transmits), or
bounces off of it, (reflects), depending on the color of the glass the light contacts, and
the frequency of that light. For example, if a sheet of magenta dichroic is illuminated
head-on, the color visible will be magenta. If that same sheet is turned to reflect light
from it's surface, the opposite color from magenta, in this case, teal, will show. And
incredibly, if the sheet is positioned at a 45º angle, a third, different color can
be seen, in this instance, yellow. A sheet of a different color will carry with it a
different set of variations, and different light sources, (natural, artificial,
florescent, incandescent, direct, indirect, candle), can produce different results. In
addition, the color of the background on which the glass is placed can make a difference,
sometimes a dramatic one, in what colors show. This effect is noticeable when the color of
clothing worn with finished jewelry made with dichroic glass is factored in.
See this page for an example of how three different background
colors produce three different glass colors, all from the same piece. As
the sample demonstrates, a progressively darker background will cause the
transmitted color to be absorbed while forcing the reflected color to be the
only one visible.
At LCB, we use a palette of up to ten different combinations of dichroic,
including some of the following, (with the first color being transmitted and the
second reflected): yellow/violet, yellow/purple, yellow/blue, pink/teal,
magenta/green, blue/gold, cyan/copper, cyan/red, cyan/dark red, cyan/dark
dark red, (really, that's what it's called), green/magenta, green/magenta
blue, green/pink, silver/clear, and red/silver blue. In addition, rainbow
dichroic, consisting of ordered spectrum colors that blend into each other
in a striped formation, is used in some projects.
Nature provides it's
own versions of the dichroic effect, such as hummingbird feathers, dragonfly wings, and
fire opals. Now, thanks to the same science that produces modern stage lighting, medical
operating room lighting, high powered telescopes, and "stealth" technology, the
jewelry profession, as well as the jewelry buyer, can benefit from the beauty and
mesmerizing effect of dichroic glass.