Creative Techniques: Interferences and Iridescents

One of the more enjoyable techniques I do is what I call “Rock of Ages”. I take pleasure in recreating the feel of ore veins we often find on rock shelves and cliffs. Of course, the real thrill is incorporating symbols and petroglyphs into the wet gel.

This technique requires inserting strips of cotton into a gel or a mixture of gels. This demands a fair amount of gel as you need to cover parts of the cotton cloth. I then weave, fold and crush segments of the cloth. I leave some of the end pieces of the cloth loose so I can choose to cut them long or short, or up to the canvas. Depending on the thickness of the gel, the painting can take up to two days to be hard to the touch. Once dried the color painting process begins. I usually will put an Interference a a base and sometimes as a topcoat over my gels. I like the refraction and bending of light that occurs. Sometimes, I also add Iridescence. So what is the difference between these two products?


An Iridescent is a highly reflective actual metals, mica platelets or synthetic. The difference between a Coarse and Fine Iridescent is simply the particulate size. These reflective pigments are either actual metals, synthetic lamellar iron oxides or naturally produced mica flakes that are mined from the earth.

You can mix any of these two products with colors and mediums to produce a myriad of colored effects. I especially enjoy Interference Oxide Red! The Iridescents are derived from mica platelets, which you often see on hikes. Golden Artist Colors groups their Iridescents into three groups based on chemical composition.

Group I: These colors are derived from mica platelets. They are then coated with an extremely thin layer of titanium dioxide. Refraction and reflection of light at the titanium dioxide layers produces various colors and pearlescent effects. Group 1 pigments include Iridescent Pearl (Coarse and Fine).

Group II: These colors are also derived from mica platelets, but an iron oxide coating causes Group II pigments to possess hues in addition to pearlescent qualities. This group includes Iridescent Gold (Coarse and Fine), Iridescent Copper and Copper Light (Coarse and Fine), and Iridescent Bronze.

Group III: A third group consists of reflective colorants that do not fit the above descriptions, including highly metallic pigments. This group includes Stainless Steel (Coarse and Fine), Micaceous Iron Oxide, and Mica Flakes (all varieties).


Interferences produce a unique reflective property. Depending on the angle with which you view your painted interference surface you will either see the actual interference color you chose in direct light or its complement in an indirect angle. So, for instance, a thin glaze of interference red in direct light will show up red but green in indirect light — so its complement or a flip if you will. This effect is particularly obvious on a dark surface.

If you are color mixing you can obtain a vast array of unique colors and adding a very small amount of black to an interference color produced an even richer lustre. If you are a “glazer” the transparency of the interference colors allows you to enhance certain landscape and wildlife features. Butterfly wings, chameleons, ocean pearl shells, ducks, fish scales and oil slicks are all effects that can be enhanced with interferences. You can put thin coats of interference over top of gels or mediums, mix then into the same, or mix varied Interferences together at once or separately. Try putting the interferences on as a base layer especially if you are doing multiple layers of glazes. To maintain the brilliance of the Interference or Iridescents it’s best to not mix them with any opaque colors or any product that has matting agent in it such as Matte Medium or matte gels. This will only serve to dull down the effect you are looking to create.

Consequently, adding glossy gels or mediums enhances the reflectivity. Thicker applications of the Interferences or Iridescent colors gives you a more pasty, opaque look so my personal recommendation is to keep your glazes and washes thin. Of course, as with all acrylics you can mix the Interferences and Iridescents with different colors and products. The more transparent the products or colors are, the richer results you’ll obtain. Anything “opaquish” will dull down your surface.

In summation, the best use of Interferences and Iridescents is to apply them in thin washes or glazes to maximize their reflective quality. One suggestion from Golden Artist Colors website I will try is to apply Interference Blue in glaze form over a light yellow or a dark red. I’m expecting some unique effects…