search  current discussion  categories  glazes - cone 4-7 

glaze test for brian gartside base, cone 6, ox. and 24 colorant tests

updated sun 5 nov 06


Alisa Liskin Clausen on sat 4 nov 06

Glaze test for Brian Gartside Base, cone 6, ox.

Source: Brian Gartside, New Zealand

Credited to Brian Gartside

Fired on mid fire white stoneware

Firing ramp with an electric controller is:
100c p/h to 600c (212f - 1112f)
150c p/h to 1140c (302f - 2084f)
80c p/h to 1220c (176f - 2228f)
15 min. soak
cool down max. to 900c (1652f)
Hold 1 hour
Shut off kiln

Recipe: by volume

Frit 3134 4 parts

EPK Kaolin 4 parts

G-200 Feldspar 2 parts

Silica 2 parts

Talc 1 part

Whiting 1 part

Water 16 parts

Colorants or additives to a 100 gram batch are measured in percent to the
100 gram batch.


The glaze base produced a transparent gloss, which unfortunately, where
double dipped and thickest, crazed on my clay body. However, many of the
colored test did not craze, or only where thick. Application could also be
a key in the success of this glaze on my clay body. However, next test, I
will test this parts recipe more precise and see if the big batch I made
was, perhaps, not precise enough. However, the base colored very well and
as Brian has used this base in over 20 years, I am sure I can adjust it to
fit my clay.

I think the sheer spectrum of colors that resulted from this base, gives a
good incentive for those who seek not to have many, many glazes in their
studios, but rather a couple of bases they can color. Personally, I think
that is an excellent idea, as I too, have two to three bases that I use
regularly, and color as I need them. I usually have a few kilos dry glaze
of each base, so that I can mix smaller amounts with coloring oxides. This
base liked RIO, Titanium and Rutile, giving some very exciting color
responses. Nr. 8, 12 and 13 all showed very nice breaking contrasts in
color. Nr. 13 yielded an especially beautiful Tenmoku glaze, with dramatic
breaking contrasts.

Here are the results of these tests.

Please go to

to see photos of the tests. I recommend double clicking on the photos to see
the best details of the glaze surface, as there are many with interesting
shells, furs, streaks, and color clarity and depth. The glazes that showed
no crazing have only been evaluated by my eyesight in the light.

1. Base

Transparent gloss. Crazed where thickest.

2. 1 Cobalt Ox.

Translucent vivid blue.

3. 2 Cobalt Ox.

Translucent darker vivid blue, .


4. 1 Cobalt Ox., 3 Rutile

Translucent brownish green ground, with vivid opalescent blue areas
where thickest. .

5. 1 Cobalt Ox., 3 RIO

Translucent, brownish green glaze.

6. 1 Cobalt Ox, 5 Ochre

Translucent, dark blue glaze with a slightly "black denim" cast.

7. 3 Rutile

Semi translucent glaze, creamy beige to yellow color. White and
slightly opalescent shell over ground color.

8. 5 Rutile

Opaque, gloss, soft white glaze, breaking beige. The glaze appearance
goes from white where thickest, to a breaking color where

the thick white disperses to tiny bubbles of white, which gives a fur
appearance, and then finally all of the white disappearing to yield a beige

where it is at it's thinnest.

9. 3 Rutile, 3 Copper Carb.

Translucent, sage green (muddy celadon) gloss, breaking clear.

10. 3 Copper Carb.

Translucent, medium green, gloss. Many translucent areas without much
color in ground green color. Crazed.

11. 6 Copper Carb.

Translucent, medium green ground, gloss, with thicker areas showing an
iridescent surface over a darker green gloss.

12. 1 Cobalt, 4 Rutile, 2 RIO

Opaque, light blue gloss glaze with some yellowish streaking where
thickest, over a brown ground with a green cast, where thinnest and

Glaze breaks with a dramatic color contrast from brown where thinnest,
to a smooth, milky blue where thickest.

Note, these colorants are the same as Floating Blue or Blue Hare.

13. 10 RIO

Opaque, gloss glaze that is a tenmoku color. Overall, the glaze is a
deep black, flushed with brown where thinner or breaking.

The brown areas have broken and dispersed edges as it they lead into
the thicker black areas.

14. 5 RIO

Semi opaque, gloss glaze. Overall dark brown color where thickest,
lighter brown similar to above where thinner. Breaking contrast is

not as dramatic as above.

15. 10 Ochre

Translucent gloss, glaze. Greenish yellow in overall cast. Crazed
where double dipped.

16. 10 Tin Ox.

Opaque, gloss, soft white glaze.

(17. 5 Tin Oxide)

Not fired

18. 10 Zircopax

Opaque, gloss white glaze. Not as white as Tin, but slightly creamy
in color.

19. ( 5 Titanium Diox.)

Not fired.

20. 10 Titanium

Semi opaque to translucent gloss, glaze. White where thickest,
giving way to a yellow ground under the white, where thinnest.

Breaks, in high contrast to the white areas, a yellow-green to orange

21. 5 RIO, 5 Titanium

Semi opaque, gloss glaze. Medium brown ground where thinnest, fur
like beige and green where thickest. Breaks brown.

22. 3 Nickel

Semi opaque, gloss glaze, dark caramel in color. Where slightly
thicker, glaze is more fluid and pools to a bluish green fur like surface.

23. 1 Tin, 1 Cobalt

Translucent, gloss dark blue glaze. Glaze crazed where thickest.

24. Pink Stain

Translucent, gloss glaze. Pink stain visible in glaze's overall
color. Glaze crazed where thickest.

25. 2 Cobalt Ox., 5 RIO

Opaque, gloss glaze. Black where thinnest, begins to turn browner
where thickest.

26. 2 Nikkel, 10 Zink

Opaque, gloss glaze. Medium caramel ground color where thinnest.
Signs of bluish-green pooling where thickest.

Regards from Alisa in Denmark