The Colorful World of Majolica: A Beautiful Low-Fire Pottery Glazing Technique Linda Arbuckle

Majolica (or maiolica) in common contemporary parlance is a white, opaque, glossy glaze that is very viscous to the point that it doesn’t move during firing. This allows line quality applied to the raw glaze to be maintained faithfully through the firing process.

The majolica technique is commonly done at low-fire temperatures, although you may work in a similar way on any stiff, opaque glaze at other temperatures with related results. Most of the stain colors used for majolica decorating will fire to mid range (cone 5–6). At cone 10, shino glazes are very viscous and don’t move much, but the available palette of colors is different: many of the purples fire out blue; yellows in reduction are often pale and grayish; most of the pinks burn out; and body stains (e.g. Mason Stain 6020 Pink) may be too refractory even at cone 10. Nevertheless, it maybe worth an experiment or two.

Opacifiers

The use of only tin as an opacifier is often modified in contemporary practice. Tin makes a lovely, buttery, very opaque, white glaze. It also increases surface tension in a glaze and may aggravate crawling problems where the glaze is thick (e.g., in corners). Tin in amounts of 5% or above will also cause a color reaction with small amounts of chrome that will cause the tin glaze to turn pink (chrome fuming). This can be delightful if anticipated, but is often not kind to your color plans as a surprise. Many of the green and teal stain colors and some black stains contain chrome, and some rutiles contain small amounts of chrome impurities that can cause chrome-tin pinking in high-tin glazes. For the above reasons, as well as the expense of tin oxide, many artists today use a zirconium opacifier, or a combination of some tin (for denser whiteness) with some zirconium opacifier. This would keep the amount of tin low (say under 4%), yet allow good opacity. Zirconium is weaker than tin in strength, and the usual rule is 1.5% zirconium to replace 1% tin. If chrome-tin pink fuming is a problem, drop the tin a bit, and add that amount multiplied by 1.5 of zirconium opacifier.

Some artists say they enjoy a bit of the terra cotta showing through a translucent white majolica glaze. For me, it darkens the glaze color, damps color response a bit, and makes any thick-thin areas of glaze application more noticeable than a more opaque white. I have always preferred a very white opaque glaze.

Majolica Colorant Suggestions

Gerstley borate production has been erratic, and the material is variable in quality. It pushes decorating colors toward pastel through very fine reticulation (break up) of the glaze surface, and although I used it when I began majolica, I now use frit as a flux (with bentonite added) or commercial majolica decorating colors.

Colorants mixed with only frit settle quickly, have limited brushability, and are very powdery once dry, making wax resist over the color smudge easily. Some artists, like Matthias Ostermann, use this powdery quality to work the movable surface like pastels. The addition of bentonite or CMC gum to the frit and colorant mix aids brushing and hardens the dry surface. Bentonite doesn’t mix easily with water, so be sure to mix dry bentonite, frit, and colorant first, then add water. Some people find an immersion blender handy. I mix small amounts and generally use a tiny whisk. If something is really lumpy, I will use a small test sieve (60 mesh) and screen the mixture.

I use Ferro frit 3124. Others will work, with color reactions influenced by the specific chemistry of each frit. To aid brushability, you may add a small amount of glycerin (drug store item), or a few drops liquid CMC gum to the liquid mix. Too much glycerin or gum can make a very slippery color mix that moves well but doesn’t apply color in an even thickness.

Colors in studio-mixed oxides or stains and commercial majolica decorating colors will generally mix, but some information about ceramic materials helps. I recommend doing line blends of colors to learn more about mixing and relative strength. Copper melts easily, and will color strongly compared to yellow colors. A nice chartreuse may be four parts yellow by volume to one part mixed copper. With paint, yellow + blue = green. In ceramic colors, blue is made with cobalt, a very strong colorant, while yellow may be a stain made with praseodymium or vanadium, which are weaker colorants than cobalt. Equal amounts of mixed yellow and blue decorating colors may still be very blue, due to the strength of cobalt.