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Raku Glazes
1. Ohi style raku: A transparent glaze with iron and manganese, resembling molasses. Where it pools it is almost black. Where thinly applied it is a dark amber.
2. Yellow raku: Yellow slip is applied before the piece is bisque fired. A clear glaze is applied for the raku firing.
3. Metallic raku: When glazes high in metallic oxides are exposed to intense reduction at low temperatures, as in the smoke chamber following raku firing, the surface becomes lustrous, oily looking, or metallic. This sample shows a combination of clear color and metallic lustre.
4. Colored raku: Various metallic oxides are mixed with the transparent glaze, or in the case of the blue, the underglaze blue is used. All are then covered with more transparent glaze to discourage a metallic surface from developing. During firing the colors have dripped and blended.
Gas Fired Glazes
5. Ash glaze: High proportion of wood ash, with some clay and feldspar. Typically, the ash glaze tends to be tan to greenish yellow and varied in color and texture throughout, with a tendency to collect in pools where it has run on the insides of plates and bowls. Wood-ash alone, or with only small amounts of clay and feldspar, makes a mottled glaze that gathers in rivulets and runs when it is thickly applied and fired high. Fired too low, it is gritty and dull gray.
6. Old Seto Glaze: This is the Old Seto Glaze over white slip brushwork. See 14 for more.
7. Chun: A semitransparent Cornwall stone, wood-ash, red clay glaze that appears opalescent due to small bubbles trapped in the glaze from the presence of magnesium in the Cornwall stone. Chun is mysterious on dark clay over a white slip.
8. Ochre Black glaze: Ochre and ash are the essential ingredients of this matte black glaze. The surface becomes slightly silvery metallic in high temperature reduction firing. However, if overfired it runs badly. Thick areas show greenish speckles, giving this glaze type the nickname "tea dust". If oxidized it appears speckled blue-black and has no green or silvery flecks.
9. and 10. Underglaze blue: A variety of clay and glaze combinations are used for this style. The glazes are stabilized by a high kaolin content so they will not run and distort the drawing. The glazes range from matt to shiny, depending on where they are placed in the kiln. Porcelain or white stoneware is generally used, but some felspathic glazes remain opaque enough to appear white while allowing the blue to show through strongly. They can be used on a toasty stoneware clay body, for a robust effect.
11. Kaki Glaze: This is the Karatsu Glaze with 10% red iron oxide.
12. Iron slip glazes: Local iron bearing clays melt to form smooth dark browns, such as found on old jugs and bottles. Varying amounts of wood-ash, feldspar, or limestone are added for black, mottled ochre-green, or a metallic red "persimmon" color.
13. Karatsu Glaze: Based on Custer spar, wood ash, red clay and kaolin, a usually gray glaze, semi-opaque, best on buff to dark stoneware. Cool blue and greenish tones develop at higher temperatures (cone 10) in heavy reduction.
14. Old Seto Glaze: A greenish transparent glaze based on wood ash, feldspar, and red clay. It is best on porcelain, light stoneware, or dark stoneware with white slip brushwork.
15. Shino: The combination of feldspar, clay, and soda ash gives this glaze it rosy blush. On stoneware the shino can appear the color of traditional red lacquer ware. A double layer gives a contrast of pearly white over the reddish tones. If very thick the opaque white "crawls" leaving areas of the clay exposed, creating even more surface interest.
16. Chun: Chun glaze flashes red when exposed to copper in the firing. This style of glazing dates back to the Sung dynasty in China.
Wood Fired Glazes
17. Flashing and dripping: In a hot part of the kiln but protected from ash buildup, this piece caught drips from the shelf above where thick natural ash glaze had built up over time. The reddish color is caused by volatile salts in the atmosphere bringing out the clay's iron content. Where the clay was completely protected it is grey-buff.
18. Fused ash: Wood ash falls on a horizontal surface and fuses leaving a natural mottles gold tone glaze.
19. Hidasuki: Wood fired with straw marking. Placed in a part of the kiln where little ash reaches it, the piece gains interest when ash from the straw placed on it leaves reddish lines.
20. Burnished red clay: Fired to bisque temperatures, the red sculpture clay is a warm sandstone hue. The burnishing smoothes the surface so that roughness will not detract from the flowing lines of the small sculpture. Burnishing is also done on pieces that will be smoked black. The clay is burnished when it becomes half hard, about the consistency of chocolate, but is not yet dry. Underneath the burnished surface, the clay is gritty.