Dichroic Glass: Dichroic literally means two colors. The color seen from light reflected off of dichroic glass is the spectral complement of the color seen by looking through it. The Dichroic coating is formed by depositing several ultra-thin mono-molecular layers of rare earth materials on glass through a process of electron discharge coating in a vacuum chamber. The brilliant dual color effect is produced by the spectral shift of light at the interface of the glass and the coating. This surface effect is very similar to the way color in bird feathers and butterfly wing scales is produced.
Normally 17 separate layers of different rare earth compounds are deposited on Standard dichroic glass and 33 are sputtered on to Premium glass which provides a separate and striking pallette of colors. Each layer has to be deposited to an exact molecular thickness to acheive the desired result. Needless to say this is a labor intensive, exacting and incredibly demanding and unforgiving process and accounts for the high price of dichroic glass.
Dichroic glass is specified by both the transmitted and the reflected colors. The colors are always categorized by the transmitted color first and the reflected Color second. EG: Yellow/purple is yellow looking through the glass towards a Light source and purple when looking at the light reflecting off of it. A computer monitor is an example of transmitted color and a painting or magazine is an example of reflected color.
Reflected colors are the most visible and brilliant on dichroic cabochons, but transparent layers add dimensionality and interesting color shifts.
Dichroic glass is coated on one side only. On transparent dichroic it can be a challenge to identify the dichroic side. You can tell which side has the coating and which does not by tilting the glass at an angle to the light. Dichroic glass is always cut on the uncoated side because the coating is very hard and will chip and damage the cutter.
Dichroic glass is offered on a variety of textured glasses. These include: ripple (a heavy wavy appearance),accordion (straight lines with different distances between the lines), granite (a gentle irregular bumpy appearance), reed (straight lines with regular distance between the lines), radium (little bumps in straight lines) and fibroid (straight ridges across the glass).
Textured dichroic coated glass stretches interestingly when the coated side is sandwiched under other glass.
Textured Dichroic Glass Examples
Dichroic Glass Patterns
Dichroic coatings are also available deposited through a pattern mask to produce complex designs with multiple colors.
Dichroic Glass Cabochons
Dichroic Glass Cabochons are produced by cutting, sawing, cleaning,arranging and layering many pieces of dichroic glass and then fusing them in a kiln
There are then several cycles of diamond grinding, reshaping, adding additional layers and elements and multiple re-firings in the Kiln till the desired result is acheived.
Finally the cabochon is fire polished one last time in the kiln, gold plated or silver findings are attached and the piece is given a good hand polishing.
The character of a dichroic cabochon is greatly affected by the glass that the dichroic is coated over. Black backed dichroics yield a brilliant reflective effect on the coated side and can be coated with a transparent glass for high gloss or left uncovered for brilliant first surface reflection or to display the exotic pearlescent results of firing a complex textured piece. (Exposed surface dichroic coatings are actually hardened and made more scratch resistant by the kiln firing process.)
Dichroic coatings over clear glass can be fused to transparent, opaque or opal glasses for a variety of effects. Over clear or light colored transparent glasses, the dichroic effect is visible from both sides and although more subtle, both reflective and transmitted colors can be realized.
Over opal or opaque glass, the dichroic effect is more pronounced and the reflected color is modified by the base glass color. Very interesting color permutations can be created this way. Sometimes a third layer of transparent dichroic is placed on the back side of an opaque or opal glass piece to give a 2 sided dichroic effect.