| To
start to unravel the many application possibilities of Dichroic
Art Glass the artist needs a fundamental knowledge of its characteristics. The
first element that needs to be understood is that the filter materials
are all clear and have no color inherent in the materials. Secondly,
there is effectively no absorption of visual light by the materials.
There are no dyes, paints or gels. Thirdly, there is a fundamental
relationship that all of the light energy is either transmitted
or reflected. The
interference filter produces the colors that we see by acting
as a selective color mirror. The color that is reflected
in the mirror is produced by the optical design of the filter.
The balance of the light that is not reflected by the selective
color mirror is transmitted. All of the light energy that
hits the surface of the filter must be accounted for in the reflected
and transmitted light, since none of the energy is absorbed.
This is in contrast to a typical piece of colored glass where
the light energy hitting the surface enters the glass and part
of the color spectrum is absorbed. The only light energy
emitting from the colored glass is the part of the spectrum that
is not absorbed.
The
colors available from the typical Dichroic designs are actually
a pair of colors from a rainbow, one in transmission and a different
one in reflection. The only difference in the filter when
producing the various colors is the thickness and number of layers
making up the filter.
The
Interference filter has the unique characteristic of shifting
its color as you change the angle of view. As you rotate
the filter from viewing directly through the filter the apparent
color changes as if the layer thickness of the stack is getting
thinner. The intermediate colors will shift down the rainbow.
The colors of a true, natural rainbow produced in our atmosphere
are usually considered to be in the sequence of violet-blue-green-yellow-orange-red.
In the typical simple single stack Dichroic Glass design, the
reflective rainbow is similar to the natural rainbow. The
transmitted rainbow is, however, in the sequence of yellow-magenta-blue-cyan.
Since green or red cannot be isolated in the transmitted rainbow
of a single stack design, a second more complex two stack design
is used that provides a transmitted rainbow similar to a neutral
rainbow. This allows the production of a sheet of Dichroic
glass that transmits red or green.
The
equipment used in the coating process has the capability of centering
the color at any pinot in the available rainbow. However,
there are technical problems associated with attaining a single
specific color, but we use our best effort to provide the desired
color.
In
the art industry there are differences in the manner of describing
the color of a given piece of Dichroic Glass. One person
may describe the color of the glass by the reflected color and
another may describe the color by the transmitted color.
Some have even gone to the extent of trying to introduce a third
color produced when the glass is viewed at any angle. Unfortunately,
there is not a standardization and all are technically correct,
but often times confusing. This coupled with the problem
of all the possible variations of the artists' perception of a
given color produces a climate for confusion and misunderstanding.
The artist must be familiar with the color relationships so that
the obvious possibilities of confusion are minimized. You
should use the "Coating Color Vs GM Identification number
Vs Fusing Color" chart for communication.
For
artists actively using Dichroic Glass, a second possibility to
eliminate confusion is to submit samples of the colors that are
desired in a given application. The artist must realize
this will only produce approximate results.
This
process should put the artist in a position of ordering and then
receiving color that will enhance the creative process.
Dichroic
Glass gives the artist another medium for self expression.
The applications are expanding daily and are limited only by the
imagination and ingenuity of the artist. |
