Reactions in glass can be very interesting when planned but if you didn’t know the potential reactiveness when setting up your design, the results can be disappointing. For example, did you ever try layering yellow and blue thinking you would get green, only to find instead you ended up with something resembling mud? This is the result of a reaction between the mineral components of the glass.
Certain glass colors will react with one another, as well as the addition of other elements like silver or copper foil into the design. Many blues and greens contain copper, while many yellows and reds contain sulfur. Vanilla Cream is also sulphur based.. In addition, there is a line of Red Reactive glass in both opal and transparent that reacts with blues especially. When these various colors and compositions come into contact with one another, the result can vary from an outline between colors to extreme changes in color. The final result will also depend on the type of glass used (transparent vs. opal), the level of heat applied and how many times the piece is fired in the kiln. Often more heat will result in more reactions.
Here are some helpful references on reactions in glass. Interested in trying some of these combinations? Create a set of small tiles and keep records of what colors or additional elements went into each. Label the backs once they’ve been fired or attach to a board and list the details below.
Oceanside Glass & Tile (96)
Here is an example of six test tiles recently fired with the same combination of reactive frit colors over various base colors. Base colors in top row, left to right: Vanilla Cream Opal, Cadet Blue (over clear), White Opal; bottom row, left to right Black Opal, Apple Jade Opal, and Turquoise Green Opal. Frits used are by Val Cox, Belgian Linen & Hawthorn.
Here is a pair of test tiles where the base colors were Almond Opal on the left and Vanilla Cream Opal on the right. I don’t recall all of the colors used without finding my old notes, however most were blues and possibly a couple of greens including Teal and Ming Green. Notice the Almond color does not react, but the Vanilla Cream, which contains sulphur, reacts quite noticeably.
Here are a few of my reactive pieces I have worked on over the past few years.