The potters herald. [volume] (East Liverpool, Ohio) 1899-1982, 1942-05-07
Gases In
Continued From Pare Onr)

ped to the consumer. is inferior. 1t is
not as il could or should be, perhaps
owing to inferior glaze surface, which
may be due to incipient spit t-out. rough
ness slight diScolorations, and lack of
brilliance. The colorS lack luSter, fresh
ness and bloom, and show II poor re-
sistance TO moderate abrasion or acid
fruit juices.
The applied metals, gold or plati-
mum, may be lacking in sheen, dull or
dry, and have certain diSfiguring
markings, or even be cracked or part
ed. Such wares, when passed to the
consumer, constitute Il serious though
intangible loss to the manufacturer.
The loss here results from lack of
buyer or consumer appeal. Such wares
appear to be faded, dreary and some
what shop worn or secondhand. The
brilliancy of the glaze quality, the
purity, gloss and trAnSlucency which
ceramic color should have is absent.
The potter generally attributes such
defects to the type of glaze used, or
to the colors used by the decorator
and the decalcOnania manufacturer,
charging that the colorS are dry, lack
ing in fluX, or will not mature at deco
rating kiln temperature, or perhaps
that the ware is simply underlined.
One is inclined to suspect that wares
of the type mentioned! are liable TO
show signs of wear on moderate abra-
sion from normal washing procedure,
or after contact with acid fruit juices
and thus contribute to no small extent
TO the all TOO numerous complaints of
color or gold wearing off. Observations
extending over n period of many years
strongly Indicate that decorating kiln
atmosphere is responsible To ma iOl
extent for the defective or inferior
decorative wares mentioned above
which constitute a very considerable
proportion of loss to manufacturers of
decorated goods.
Gaseous matter present in the deco
rating kiln results not only from pro
ducts of fuel combustion, but also
from the YolHtiliZation of oils, var
nShcS and other mediums used in the
application of decorations.
In addition. certain cnlors. fluXcs
and amalgamS of gold, mercury, or
platinum at critical temperatures give
off omanationS, volatile substances and
diSti!latoS which condCnSe or sublime
and which are deposited on ware in
the cooler zones Of the kiln.
ically and dctrimcntally With the ap-
piled cooIS and metals: or are deposit
ed ON, and in some instances are alb
sOrb@d by, the glaze or CoIorS applied
as decorations. At higher tcmpera-
| ture such depo%itiNlS VolatiliZc with
greater or lesser i'll effects to the ware
Examples of the effects of yoIatili-
ZHtion from The color or metals are
numorouS: for example:
In decorating kims giiing large pro
portions of bUrniSh goid-ta gold-mrI-
curry amalgam the mercury yolatiI-
/ ICES and v#puurs condcnSc on wares
in the cooler zones of the kiln, destroy
! ing the brightness of any liquid bright
/ gold decorations which may lie in the
| track or path of the vapUriZcd mel-
curry.
Where certain types of antinonait
yellow CoIorS are prCpondrrant in tho
| Kiln. lead anlimuniate vOlatiIizcS and
attacks applied gold and adversely af-
fcctS other colorS in close proximity
j. Robson in Il paper (JoUmal \. G.
! s.. V. Is. 1889 discusses the ill Of
fcctS of VolatiliZatiOn of Il Sclenium REQ
ovcrglaZc color.
1t was shown that when placed toe
! close together, there was Il tendency
for the color glaze 10 daricn in StrealiS
due To volatiization and subsequent
condensation OF seIenum lead fumc>
/ from one piece TO another in close
proximity.
by placing the ware ON Il lower deck
of the llih-Wilh no bat or shell above
and each piece spaced about three
/ inches apart. this condensation was
avoided as was also the effect of Siz,
ing fumes from decal ware ahead OF
| il in the tunnel.
TO appreciate the comploXity and