Charles Moore on sun 4 mar 01
Your assistance, Clayarters,
Does sunlight damage glazes?
More specifically, will exposure to sunlight damage glazes from early in =
the 20th century? I have a collection of American art pottery sitting =
along a south double-panned window. A fellow art pottery collector has =
told me that I should move the pottery to avoid damage, especially =
fading.
Though some American art pottery was glaze fired at relatively high =
temperatures, much of it was low-fired ware.
Is my friend correct? Or would I need to know the composition of the =
glazes?
Charles Moore
camoore33@earthlink.net
Tom Buck on mon 5 mar 01
Charles:
if your pots underwent the reduction process during their
formation, then it is possible strong light ("energetic visible light
photons" perhaps with ultra-violet and infra-red photons too) may have an
affect in your pots in the window. Especially if copper-hued pots
(metallic and red colour) were produced during the reduction activities.
I exposed a bright-penny Raku plate outdoors for three months in
bright summer sunlight. When I brought it indoors, the copper had changed
from penny colour to red lustre, and a fairly dark one at that. And these
lustres were ones I had adjusted to make them impervious to atmospheric
gases. The four lustres I reformulated stayed as is, even in sunlight,
except for the bright penny lustre.
Now, there are other metallics that change from oxide to metal
during reduction firing (wood fuel, gas fuel, other fossil fuel). But it
is difficult to talk about these without a specific example. So, if your
pots are not the well-known iron brown glaze from natural high-iron clay
(eg, Albany slip), but contain other hues, it might be wise to check on
where the pots were stored previously, etc. And if you value them, move
them away from the window.
til later. Peace. Tom B.
)
tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street,
Hamilton ON L8T 3E1 Canada
On Sun, 4 Mar 2001, Charles Moore wrote:
> Your assistance, Clayarters,
>
> Does sunlight damage glazes?
>
> More specifically, will exposure to sunlight damage glazes from early in the 20th century? I have a collection of American art pottery sitting along a south double-panned window. A fellow art pottery collector has told me that I should move the pottery to avoid damage, especially fading.
>
> Though some American art pottery was glaze fired at relatively high temperatures, much of it was low-fired ware.
>
> Is my friend correct? Or would I need to know the composition of the glazes?
>
> Charles Moore
> camoore33@earthlink.net
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
Janet Kaiser on tue 6 mar 01
In a word, YES. Sunlight per se will not damage
most ceramic vessels, but a south facing window
is not a good idea. I have found that only glass
is OK in that situation. I believe it has more
to do with repetitive heating and cooling
cycles. When you think about it, that is similar
to putting your collection into a dishwasher
once a day, albeit without detergent and water!
Although that said, three low-fired earthenware
pitchers which have been on the bedroom sill
about six years, have crazed badly and faded on
the window side. That must be the light
affecting them as much as the temperature
fluctuations.
On the whole, antiques of any kind, including
Victoriana and early 20th century work of any
kind should be kept out of constant sunlight. It
was made on the understanding that the curtains
(drapes) would exclude daylight and preserve
colours. Bright sunny rooms are a modern
phenomena.
Janet Kaiser - suffering from an attack of
Hexenschuß (witch's shot) or lower back pain and
very uncomfortable. Have you fellow sufferers
noticed how the knock on effects of back pain
(swollen stomach, constipation, headaches) are
as bad as the back itself?
The Chapel of Art . Capel Celfyddyd
HOME OF THE INTERNATIONAL POTTERS' PATH
Criccieth LL52 0EA, GB-Wales Tel: (01766) 523570
E-mail: postbox@the-coa.org.uk
WEBSITE: http://www.the-coa.org.uk
----- Original Message -----
Does sunlight damage glazes?
______________________________________________________________________________
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Janet Kaiser on tue 6 mar 01
In a word, YES. Sunlight per se will not damage
most ceramic vessels, but a south facing window
is not a good idea. I have found that only glass
is OK in that situation. I believe it has more
to do with repetitive heating and cooling
cycles. When you think about it, that is similar
to putting your collection into a dishwasher
once a day, albeit without detergent and water!
Although that said, three low-fired earthenware
pitchers which have been on the bedroom sill
about six years, have crazed badly and faded on
the window side. That must be the light
affecting them as much as the temperature
fluctuations.
On the whole, antiques of any kind, including
Victoriana and early 20th century work of any
kind should be kept out of constant sunlight. It
was made on the understanding that the curtains
(drapes) would exclude daylight and preserve
colours. Bright sunny rooms are a modern
phenomena.
Janet Kaiser - suffering from an attack of
Hexenschuß (witch's shot) or lower back pain and
very uncomfortable. Have you fellow sufferers
noticed how the knock on effects of back pain
(swollen stomach, constipation, headaches) are
as bad as the back itself?
The Chapel of Art . Capel Celfyddyd
HOME OF THE INTERNATIONAL POTTERS' PATH
Criccieth LL52 0EA, GB-Wales Tel: (01766) 523570
E-mail: postbox@the-coa.org.uk
WEBSITE: http://www.the-coa.org.uk
----- Original Message -----
Does sunlight damage glazes?
ferenc jakab on wed 7 mar 01
> In a word, YES. Sunlight per se will not damage
> most ceramic vessels, but a south facing window
> is not a good idea.
Janet,
depends on your hemisphere (Earth not brain). Here a South facing window is
definitely a GOOD idea.
Feri.
Sitting in the shade on the south verandah, sipping iced coffee and enjoying
the 'roos down by the dam.
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