Chrome Colors
The glazes discussed here contain 0.02% chrome oxide.
Previous tests show that the glaze tsabar-chrome_Z2D is blue:
Then, with a shift to higher BaO, the glaze tsabar-chrome-Z2D-2F becomes blue
overlaid with yellow.
With a further shift of CaO to BaO, the result is a glaze
tsabar-chrome-Z2D-2F-2I-0 which is chartreuse.
In these current tests shown here, the shift in the alkaline earth components
of the glaze is in the other direction;
With an increase in alumina as well, the glaze tsabar-chrome-Z2D-2L_1 becomes
matte, and its color has migrated to raspberry.
All of the BaO replaced by CaO.
inside of bowl:
Outside of bowl:
All of the BaO replaced by CaO, and increased Alumina.
inside of bowl:
Outside of bowl:
150 deg F an hour to 250 deg F
400 deg F an hour to 1800 deg F
300 deg F an hour to 2050 deg F
120 deg F an hour to 2310 deg F with a hold of 20 minutes at 2310 deg F
300 deg F an hour to 1750 deg F then a half hour hold at 1750 deg F
300 deg F an hour to 1700 deg F then a Three hour hold at 1700 deg F
25 deg F an hour to 1650 deg F then a one hour hold at 1650 deg F
K2O 0.06
Al2O3 0.41
SiO2 2.3
molecular percent Silica 60%
This glaze has .2% Chrome Oxide added
K2O 0.08
Al2O3 0.45
SiO2 2.3
molecular percent Silica 59%
This glaze has .2% Chrome Oxide added
As expected, the lower alumina glaze tsabar-chrome-Z2D-2L_0 is glossier;
it also has a less saturated color,
The higher alumina glaze tsabar-chrome-Z2D-2L_1 has a more saturated color,
though is on the edge of underfired.
It's tempting to conclude that all other oxide components equal, higher CaO
pushes the color of a glaze containing chrome toward red.
These glazes are interesting as an indication of the effect of CaO on the
color of chrome.
all of the BaO is replaced by CaO to
get a chrome red glaze, tsabar-chrome-Z2D-2L_0.
tsabar-chrome-Z2D-2L_0
bowl is ~3 inches in diameter
tsabar-chrome-Z2D-2L_1
bowl is ~3 inches in diameter
oxidation firing to cone 10 in an electric kiln
Firing profiles
Up Fire profile
Down Fire Profile
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
glaze compositions
Empirical Formula glaze tsabar-chrome-Z2D-2L_0 :
Na2O 0.20
CaO 0.73
MgO 0.01
SnO2 0.14
Empirical Formula glaze tsabar-chrome-Z2D-2L_1 :
Na2O 0.19
CaO 0.72
MgO 0.01
SnO2 0.14
Remarks
showing the red only where the glaze is
applied thickly.