DICHRO TECHNICAL INFO
A word about dichroic jewelry.
The color of a piece of dichroic jewelry depends on the direction in which it is viewed. For example, the color CC stands for cyan-copper. When the coating is placed on clear glass, the cyan is the transmitted color seen when viewing the glass straight-on through a light or window. The copper is the reflected color seen when viewing the glass against a dark background. As the glass is turned in your view, the shades of color vary between these colors. These pictures demonstrate this.
Cyan-copper dichoric looking straight through the glass.
This is the same glass looking at an approximate 45 degree angle
The same glass looking at it against a dark background.
Howard Sandberg produces the finest dichroic coatings in this country targeted for the artist community. These dichroic coatings are put through rigorous testing to ensure that you will have the finest quality product. The colors are consistently vibrant and remain intact under "Burn Out" conditons that many competitors glass has not held up to. Ask the professonal dichroic artist which glass is best and you will hear "Coatings By Sandberg".
Dichroic glass has two primary colors. The Transmitted color as seen when holding the glass to the light and the Reflected color seen when the glass is placed against a dark background. ie: magenta/green
Colors are named for the transmitted/reflected color of each piece and coded by the first letter of each color.
For example, YP = Yellow/Purple, where Yellow is the transmitted color and Purple is the reflected color.
Note: If you fuse dichroic to an dark base, you will only see the reflected color.
Dichroic sheet glass comes in the following sizes.
Note: Sheets have flat edges on one side where the machines hold them for coating.
- Full size: 19" diameter (about 2 sq. ft.)
- Half Size: 1/2 of a 19" diameter (about 1 sq. ft.)
- Quarter size: 1/4" of a 19" diameter (about .5 sq. ft.)
- 4" x 4" size: Medium size (16 sq. inches.)
- 2" x 4": Jewelry size (8 sq. inches)
MORE TECHNICAL INFO
"Dichroic" is defined as the property of having more than one color, especially when viewed from different angles. Dichroic glass is a high-tech spin-off of the space industry.
Thin layers of metallic oxides, such as titanium, silicon, and magnesium are deposited upon the surface of the glass in a high temperature, vacuum furnace.
The glass to be coated is carefully cleaned, and fastened to a planetary arm in the top of the furnace chamber. The oxides are placed in a crucible on the bottom of the chamber. Air inside of the chamber is removed with a high vacuum-producing cryopump, and the chamber is heated to 300oF. The metallic oxides are vaporized by an electron beam and the rotating glass target is evenly coated with many thin
layers. The resulting color is determined by the individual oxide compositions.
Dichroic coatings transmit certain wavelengths of light, while reflecting others, thus creating an interference-effect similar to the iridescence observed in Nature's fire opal, dragonfly wings and hummingbird feathers. The transmitted color is different than the reflected color, and a third color is produced by viewing the dichroic piece at a 45 degree angle. The resulting colors are pure, saturated, single wavelengths of light, that appear to originate from within the dichroic piece.
Howard Sandberg, owner of "Coatings by Sandberg, takes special precautions to insure his coatings have outstanding brilliance and viability - that is why we selected them as our supplier. The naming of Dichroic Coated Glass is a confusing topic for the artist as well as the manufactuer since there is no industry standard. Using the transmitted light and reflected light to describe the glass seems reasonable and some manufacturers use this scheme.
When the Dichroic Coated Glass is fused or otherwise hotworked, the color will permanenly shift toward the next higher color. The amount of shift must experimentally determined. It is a good idea to make a test strip, a part of which is shown below.
COLOR-SHIFTS WHEN HOTWORKING CBS DICHROIC GLASS
STANDARD COLORS (Y/V to C/DDR)
When CBS Standard Color Dichroic Glass is fused or otherwise hot worked the color will permanently shift toward the next lighter color (moving toward Y/V). This is a key point in understanding the process that Coatings By Sandberg has taken in the creation of its Standard Colors.
For example; apiece of CYAN/COPPER when fused will become more like a BLUE/GOLD sheet. The exact amount of color shift must be experimentally determined by the Artist for the particular process being used. The shift will be dependent on the highest temperature and the length of time that the coating is exposed to the elevated temperatures. After some experimentation the Artist will be able to predict the colors that should be used to reach the end result desired. In general, the color of a sheet of Dichroic glass while looking at it from a 45 degree angle, will look like the end result color when hot worked (This rule applies to all CBS Dichroic colors). This is a quick way to estimate what final color an artist is looking for.
Specialty Colors were created in response to customer input as well as experimental design. Our success at creating a brilliant reflective color is evident. These specialty colors, when fused or otherwise hot worked, remain relatively the same color. With a minimal shift these colors remain their true vibrant color whether coated on black glass or clear glass. (Note: The transmitted color is not noted due to the fact that these colors were created mainly for their reflective properties, but they have become just as popular on clear glass as on black glass.)
Premium Colors also remain relatively the same color when fused or otherwise hot worked. Green/Magenta is the only exception. This Dichroic color shifts to an intense Hot-Pink.
Patterns are all coated in a “Rainbow Configuration.” This means that a Dichroic coated pattern sheet will have all the colors of the rainbow in a gentle arch across the sheet. For example: A square pattern will have uniform squares across the entire sheet as the squares gradually change from one color to the next in an arch from one side of the sheet to the other. When fused or otherwise hot worked, each color of the rainbow will shift toward one color lighter, much like the standard color’s shift. For example: The CYAN/COPPER section of the pattern sheet will shift toward BLUE/GOLD, etc.
Specialty Patterns are rainbow stripes in varying degrees of width, repeating in straight rows across the glass sheet. Once again, each color of the rainbow will shift one color lighter when fused or otherwise hot worked.
MAKING TEST STRIPS
Take make a strip use Bullseye clear (1101.50 thin) glass. Cut base plate of sufficient width and then fuse small samples of dichroic glass onto it, using another piece of clear as a cap.
Below the fused glass, glue another original piece of dichroic glass. You now have a visual
measurement of the shift in color created when fusing dichroic.