Email digest for the Global Conservation Forum (ConsDistList) egroup.
------------------------------------------------------------------------------------------------------------
1. CFP | Participation and Community Involvement in the Conservation of
Contemporary Art in Institutional Collections / ICOM-CC Virtual Joint Interim
Meeting
2. RE: Degradation of light yellow glass in leadlights in insulating glass
units
3. RE: Degradation of light yellow glass in leadlights in insulating glass
units
4. RE: Degradation of light yellow glass in leadlights in insulating glass
units
5. RE: Degradation of light yellow glass in leadlights in insulating glass
units
6. Holiday edition 2025 - Newsletter on Polychromed wooden sculpture
conservation and study (free online resources)
7. RE: "Collecting and Preserving Colour Photographs at the Art Institute of
Chicago" lecture by Sylvie Penichon
------------------------------------------------------------------------------------------------------------
1.From: Aga Wielocha
Posted: Thursday December 11, 2025 6:06 AM
Subject: CFP | Participation and Community Involvement in the Conservation of
Contemporary Art in Institutional Collections / ICOM-CC Virtual Joint Interim
Meeting
Message: CFP | Participation and Community Involvement in the Conservation of
Contemporary Art in Institutional Collections / ICOM-CC Virtual Joint Interim
Meeting
This is a reminder about the upcoming deadline [20 December 2025] for
submitting proposals for case studies of community participation in the
conservation of contemporary art within institutional collections.
Title: Participation and Community Involvement in the Conservation of
Contemporary Art in Institutional Collections
Organisers: ICOM-CCs Theory, History, and Ethics of Conservation Working Group
and the Modern Materials and Contemporary Art Working Group
Date: 19 February 2026
Where: ICOM-CC Zoom platform
We invite proposals for 15-minute presentations highlighting both successful
and unsuccessful examples of participation and community involvement in the
conservation of contemporary art in public collections. The goal of the meeting
is to examine how contemporary art conservation practices are involving
communities, the value of expert knowledge in these settings, and the
challenges that arise in practice. How do institutional practices maintain
professional standards while working with communities, and what roles do
conservation professionals assume in these contexts? What does community
participation look like beyond the assumed binary between conservation
professionals and non-experts? How are diverse perspectives brought together,
and how is (or isnt) consensus achieved?
While the meeting aims to map existing practices, we also welcome presentations
showcasing projects and initiatives currently under development, slated for
implementation in the near future.
Please find the full Call for Presentations attached for more details or
download it here:
https://www.icom-cc.org/en/downloads/call-for-presentations-modern-mate...
<https://www.icom-cc.org/en/downloads/call-for-presentations-modern-materials-contemporary-art_theory-history-and-ethics-of-conservation-working-groups-february-2026>-
2.From: Sarah Benrubi
Posted: Thursday December 11, 2025 7:07 AM
Subject: RE: Degradation of light yellow glass in leadlights in insulating
glass units
Message:
Dear Janneke,
According to Barry probably crizzling/atmospheric degradation. This is quite
complex to evaluate exactly de source but maybe the first thing to do is to
reduce the humidity around 40%. Then will come all the research ;-)
About literature:
- here are a few from the Corning Museum :
https://info.cmog.org/conservation/conservation-research-and-publications#deterioration
<https://info.cmog.org/conservation/conservation-research-and-publications#deterioration>
and if you contact the library at the Museum they will send you a more
extensive list about Crizzling.
- Robert Brill who was scientific glass expert at the Museum published a lot
about the subject
- Articles from Jerzy Kunicki-Goldfinger are very useful !
- close to you Guus Verhaar also did some publication
- about interaction metal /class (not sure it is the purpose hier) you have
publications from Gerrart Eggert
- in the conservation glass book from Stephen Koob, few pages are dedicated to
crizzling and how to adapt the environment of the concerned object.
hope this will help
Sarah Benrubi
--
Conservation-restauration d'oeuvres d'art
Céramique et verre
-------------------------------------------
Original Message:
Sent: 12/10/2025 12:17:00 PM
From: Barry Knight
Subject: RE: Degradation of light yellow glass in leadlights in insulating
glass units
Dear Janneke,
It's a bit hard to tell from your photo, but this looks rather like crizzling.
If the surface of the glass has become depleted in alkali metal ions by
leaching, it may shrink and flake off when moved from its original cold, high
RH environment to a warmer, low RH environment inside the protective glazing.
The surface behaves more like silica gel: it shrinks when it is dehydrated.
What is the composition of the glass? Is it particularly susceptible to
leaching? Does the flaking only occur on the original external side, or on both
sides?
Best wishes,
------------------------------
Barry Knight
Conservation Scientist
St Albans
UK
------------------------------
-------------------------------------------
Original Message:
Sent: 12-08-2025 11:10
From: Janneke van der Stok
Subject: Degradation of light yellow glass in leadlights in insulating glass
units
Dear community,
Recently, several glaziers in the Netherlands have experienced a very peculiar
degradation phenomenon in historic light yellow glass. When present in a lead
panel, and subsequently placed in an insulating glass unit, the surface of the
glass starts to flake off in a specific pattern, making the glass
semi-transparent (see attached image). This process can already take place
after a few weeks. It appears that light yellow mouthblown cylinder glass with
a slightly undulated surface (often called Goethe glass) from around 100 years
old is specifically prone to this.
We, at the Cultural Heritage Agency of the Netherlands, would now like to know
what is actually happening and why, so that we can identify glass at risk and
try to prevent this from taking place in the future. There are a lot of
variables playing a possible role: the microclimate with elevated temperatures,
relative humidity, possible offgassing of putty/sealant/solder/…, the glass
composition, the production process of the glass, the 'thermal history of the
glass', the orientation of the window, et cetera.
So as a start, we would like to know whether anyone has comparable experiences,
and is willing to share this with us? Can anyone guide us towards literature
about this very specific degradation phenomenon? Any other ideas are also very
much appreciated!
Thanks a lot for your help!
With kind regards,
Janneke van der Stok
Janneke van der Stok, Ph.D.
specialist (building) materials: glass, metal & cork
...........................................................................................
Ministry of Education, Culture and Science
Cultural Heritage Agency of the Netherlands
Smallepad 5 | 3811 MG | Amersfoort
P.O. Box 1600 | 3800 BP | Amersfoort | the Netherlands
...........................................................................................
T +31 6 50 08 99 58 <tel:+31 6 50 08 99 58>
E [email protected] <[email protected]>
...........................................................................................
present: Mo; Tue morning; Thu; Fri
...........................................................................................
------------------------------
Janneke van der Stok
Materials specialist (glass, metal, cork)
Cultural Heritage Agency of the Netherlands
------------------------------
3.From: Janneke van der Stok
Posted: Thursday December 11, 2025 8:34 AM
Subject: RE: Degradation of light yellow glass in leadlights in insulating
glass units
Message:
Dear Barry,
Thank you for your suggestions! We have yet to start the analyses, so nothing
yet on the composition. Stephen Koob also suggested to me (out of this thread)
that it might be a result of an unstable composition, most likely with too much
alkali in the glass.
I'm not sure yet about the sides on which it appears, as I am still awaiting
more case studies and material. At least one person mentioned on both sides.
And the crizzling would then happen quite fast! There are at least two Dutch
glaziers who test the glass by using a hair blower on a piece of yellow glass,
and often this surface 'structure' then appears almost instantly, as far as I
understood. Of course I will contact them for further details.
All the best,
Janneke
------------------------------
Janneke van der Stok
Materials specialist (glass, metal, cork)
Cultural Heritage Agency of the Netherlands
------------------------------
-------------------------------------------
Original Message:
Sent: 12-10-2025 12:16
From: Barry Knight
Subject: Degradation of light yellow glass in leadlights in insulating glass
units
Dear Janneke,
It's a bit hard to tell from your photo, but this looks rather like crizzling.
If the surface of the glass has become depleted in alkali metal ions by
leaching, it may shrink and flake off when moved from its original cold, high
RH environment to a warmer, low RH environment inside the protective glazing.
The surface behaves more like silica gel: it shrinks when it is dehydrated.
What is the composition of the glass? Is it particularly susceptible to
leaching? Does the flaking only occur on the original external side, or on both
sides?
Best wishes,
------------------------------
Barry Knight
Conservation Scientist
St Albans
UK
------------------------------
Original Message:
Sent: 12-08-2025 11:10
From: Janneke van der Stok
Subject: Degradation of light yellow glass in leadlights in insulating glass
units
Dear community,
Recently, several glaziers in the Netherlands have experienced a very peculiar
degradation phenomenon in historic light yellow glass. When present in a lead
panel, and subsequently placed in an insulating glass unit, the surface of the
glass starts to flake off in a specific pattern, making the glass
semi-transparent (see attached image). This process can already take place
after a few weeks. It appears that light yellow mouthblown cylinder glass with
a slightly undulated surface (often called Goethe glass) from around 100 years
old is specifically prone to this.
We, at the Cultural Heritage Agency of the Netherlands, would now like to know
what is actually happening and why, so that we can identify glass at risk and
try to prevent this from taking place in the future. There are a lot of
variables playing a possible role: the microclimate with elevated temperatures,
relative humidity, possible offgassing of putty/sealant/solder/…, the glass
composition, the production process of the glass, the 'thermal history of the
glass', the orientation of the window, et cetera.
So as a start, we would like to know whether anyone has comparable experiences,
and is willing to share this with us? Can anyone guide us towards literature
about this very specific degradation phenomenon? Any other ideas are also very
much appreciated!
Thanks a lot for your help!
With kind regards,
Janneke van der Stok
Janneke van der Stok, Ph.D.
specialist (building) materials: glass, metal & cork
...........................................................................................
Ministry of Education, Culture and Science
Cultural Heritage Agency of the Netherlands
Smallepad 5 | 3811 MG | Amersfoort
P.O. Box 1600 | 3800 BP | Amersfoort | the Netherlands
...........................................................................................
T +31 6 50 08 99 58
E [email protected] <[email protected]>
...........................................................................................
present: Mo; Tue morning; Thu; Fri
...........................................................................................
------------------------------
Janneke van der Stok
Materials specialist (glass, metal, cork)
Cultural Heritage Agency of the Netherlands
------------------------------
4.From: Janneke van der Stok
Posted: Thursday December 11, 2025 8:34 AM
Subject: RE: Degradation of light yellow glass in leadlights in insulating
glass units
Message:
Dear Sarah,
Thanks a lot for your extensive reply! Interesting that you also say that the
relative humidity might be a significant factor. We will certainly look into
that!
And a nice list of literature, with a few people that are luckily already on my
to-contact list. Others I will check because of your valuable addition. Gerhard
Eggert also replied me by e-mail, he said that it doesn't look like corrosion
as we know it, and he suggested to test for a possible coating.
Your help is much appreciated!
All the best,
Janneke
------------------------------
Janneke van der Stok
Materials specialist (glass, metal, cork)
Cultural Heritage Agency of the Netherlands
------------------------------
-------------------------------------------
Original Message:
Sent: 12-11-2025 06:21
From: Sarah Benrubi
Subject: Degradation of light yellow glass in leadlights in insulating glass
units
Dear Janneke,According to Barry probably crizzling/atmospheric degradation.
This is quite complex to evaluate exactly de source but maybe the first thing
to do is to reduce the humidity around 40%. Then will come all the research ;-)
About literature: - here are a few from the Corning Museum :
https://info.cmog.org/conservation/conservation-research-and-publications#deterioration
<https://info.cmog.org/conservation/conservation-research-and-publications#deterioration>
and if you contact the library at the Museum they will send you a more
extensive list about Crizzling.- Robert Brill who was scientific glass expert
at the Museum published a lot about the subject - Articles from Jerzy
Kunicki-Goldfinger are very useful !- close to you Guus Verhaar also did some
publication- about interaction metal /class (not sure it is the purpose hier)
you have publications from Gerrart Eggert- in the conservation glass book from
Stephen Koob, few pages are dedicated to crizzling and how to adapt
the environment of the concerned object. hope this will helpSarah Benrubi--
Conservation-restauration d'oeuvres d'art
Céramique et verre
Original Message:
Sent: 12/10/2025 12:17:00 PM
From: Barry Knight
Subject: RE: Degradation of light yellow glass in leadlights in insulating
glass units
Dear Janneke,
It's a bit hard to tell from your photo, but this looks rather like crizzling.
If the surface of the glass has become depleted in alkali metal ions by
leaching, it may shrink and flake off when moved from its original cold, high
RH environment to a warmer, low RH environment inside the protective glazing.
The surface behaves more like silica gel: it shrinks when it is dehydrated.
What is the composition of the glass? Is it particularly susceptible to
leaching? Does the flaking only occur on the original external side, or on both
sides?
Best wishes,
------------------------------
Barry Knight
Conservation Scientist
St Albans
UK
------------------------------
Original Message:
Sent: 12-08-2025 11:10
From: Janneke van der Stok
Subject: Degradation of light yellow glass in leadlights in insulating glass
units
Dear community,
Recently, several glaziers in the Netherlands have experienced a very peculiar
degradation phenomenon in historic light yellow glass. When present in a lead
panel, and subsequently placed in an insulating glass unit, the surface of the
glass starts to flake off in a specific pattern, making the glass
semi-transparent (see attached image). This process can already take place
after a few weeks. It appears that light yellow mouthblown cylinder glass with
a slightly undulated surface (often called Goethe glass) from around 100 years
old is specifically prone to this.
We, at the Cultural Heritage Agency of the Netherlands, would now like to know
what is actually happening and why, so that we can identify glass at risk and
try to prevent this from taking place in the future. There are a lot of
variables playing a possible role: the microclimate with elevated temperatures,
relative humidity, possible offgassing of putty/sealant/solder/…, the glass
composition, the production process of the glass, the 'thermal history of the
glass', the orientation of the window, et cetera.
So as a start, we would like to know whether anyone has comparable experiences,
and is willing to share this with us? Can anyone guide us towards literature
about this very specific degradation phenomenon? Any other ideas are also very
much appreciated!
Thanks a lot for your help!
With kind regards,
Janneke van der Stok
Janneke van der Stok, Ph.D.
specialist (building) materials: glass, metal & cork
...........................................................................................
Ministry of Education, Culture and Science
Cultural Heritage Agency of the Netherlands
Smallepad 5 | 3811 MG | Amersfoort
P.O. Box 1600 | 3800 BP | Amersfoort | the Netherlands
...........................................................................................
T +31 6 50 08 99 58
E [email protected] <[email protected]>
...........................................................................................
present: Mo; Tue morning; Thu; Fri
...........................................................................................
------------------------------
Janneke van der Stok
Materials specialist (glass, metal, cork)
Cultural Heritage Agency of the Netherlands
------------------------------
5.From: Barry Knight
Posted: Thursday December 11, 2025 12:35 PM
Subject: RE: Degradation of light yellow glass in leadlights in insulating
glass units
Message:
Dear Janneke,
If I am right, your problem is caused by low relative humidity. You need to
keep the RH high - maybe 70-80% - to prevent the depleted surface layer from
dehydrating, shrinking and flaking off.
Best wishes,
Barry
------------------------------
Barry Knight
Conservation Scientist
St Albans
UK
------------------------------
-------------------------------------------
Original Message:
Sent: 12-10-2025 12:16
From: Barry Knight
Subject: Degradation of light yellow glass in leadlights in insulating glass
units
Dear Janneke,
It's a bit hard to tell from your photo, but this looks rather like crizzling.
If the surface of the glass has become depleted in alkali metal ions by
leaching, it may shrink and flake off when moved from its original cold, high
RH environment to a warmer, low RH environment inside the protective glazing.
The surface behaves more like silica gel: it shrinks when it is dehydrated.
What is the composition of the glass? Is it particularly susceptible to
leaching? Does the flaking only occur on the original external side, or on both
sides?
Best wishes,
------------------------------
Barry Knight
Conservation Scientist
St Albans
UK
------------------------------
Original Message:
Sent: 12-08-2025 11:10
From: Janneke van der Stok
Subject: Degradation of light yellow glass in leadlights in insulating glass
units
Dear community,
Recently, several glaziers in the Netherlands have experienced a very peculiar
degradation phenomenon in historic light yellow glass. When present in a lead
panel, and subsequently placed in an insulating glass unit, the surface of the
glass starts to flake off in a specific pattern, making the glass
semi-transparent (see attached image). This process can already take place
after a few weeks. It appears that light yellow mouthblown cylinder glass with
a slightly undulated surface (often called Goethe glass) from around 100 years
old is specifically prone to this.
We, at the Cultural Heritage Agency of the Netherlands, would now like to know
what is actually happening and why, so that we can identify glass at risk and
try to prevent this from taking place in the future. There are a lot of
variables playing a possible role: the microclimate with elevated temperatures,
relative humidity, possible offgassing of putty/sealant/solder/…, the glass
composition, the production process of the glass, the 'thermal history of the
glass', the orientation of the window, et cetera.
So as a start, we would like to know whether anyone has comparable experiences,
and is willing to share this with us? Can anyone guide us towards literature
about this very specific degradation phenomenon? Any other ideas are also very
much appreciated!
Thanks a lot for your help!
With kind regards,
Janneke van der Stok
Janneke van der Stok, Ph.D.
specialist (building) materials: glass, metal & cork
...........................................................................................
Ministry of Education, Culture and Science
Cultural Heritage Agency of the Netherlands
Smallepad 5 | 3811 MG | Amersfoort
P.O. Box 1600 | 3800 BP | Amersfoort | the Netherlands
...........................................................................................
T +31 6 50 08 99 58
E [email protected] <[email protected]>
...........................................................................................
present: Mo; Tue morning; Thu; Fri
...........................................................................................
------------------------------
Janneke van der Stok
Materials specialist (glass, metal, cork)
Cultural Heritage Agency of the Netherlands
------------------------------
6.From: Marta Estadella Colomé
Posted: Thursday December 11, 2025 8:48 PM
Subject: Holiday edition 2025 - Newsletter on Polychromed wooden sculpture
conservation and study (free online resources)
Message:
Dear Colleagues and Students,
I'm sharing here the link to the holiday edition 2025 post of Polychromed
Wooden Sculpture: a love letter, written by the italian paintings and
polychromed sculptures conservator Vincenzo Amato (many thanks Vincenzo to
agree to do it!).
PWSALL It is a newsletter published bi-monthly on Fridays for a year. The aim
is nothing more than to highlight interesting online free resources and links
on the conservation and study of polychromed wooden sculptures. Also, it's a
project solely done for fun! Although we close it a while ago we keep it open
for these holidays editions written by guest colleagues. Hoping to see you
there.
https://polychromedwoodensculpture.substack.com
<https://polychromedwoodensculpture.substack.com/>
Best,
------------------------------
Marta Estadella Colomé
Polychrome Wooden Sculpture Conservator
------------------------------
7.From: Sarah Lowengard
Posted: Thursday December 11, 2025 8:49 PM
Subject: RE: "Collecting and Preserving Colour Photographs at the Art
Institute of Chicago" lecture by Sylvie Penichon
Message:
Dear Ms. Ng
I find this post a bit confusing. Will the presentation be broadcast live, or
would I need to be in Singapore to attend?
The links go only to a registration form with no further indication.
Thank you.
------------------------------
Sarah Lowengard
New York
United States
------------------------------
-------------------------------------------
Original Message:
Sent: 12-10-2025 01:36
From: Esther Ng
Subject: "Collecting and Preserving Colour Photographs at the Art Institute of
Chicago" lecture by Sylvie Penichon
Dear All,
The Heritage conservation centre of Singapore is pleased to announce that
Sylvie Pénichon, Director of Paper, Photography and Media conservation at the
Art Institute of Chicago, will be giving a public lecture on "Collecting and
Preserving Colour Photographs at the Art Institute of Chicago" on Monday, 5
January 2026, 3.00 – 4.00 pm. The talk details are below. Please register for
the talk here: https://form.jotform.com/253380760012044
<https://form.jotform.com/253380760012044>
This talk is co-organised with the National Gallery of Singapore.
<https://form.jotform.com/253380760012044>
Registration for "Collecting and Preserving Color Photographs at the
Art...Please click the link to complete this form.
<https://form.jotform.com/253380760012044>
Kind regards,
Esther
You are subscribed to "Global Conservation Forum (ConsDistList)" as
[email protected]. To change your subscriptions, go to
http://community.culturalheritage.org/preferences?section=Subscriptions. To
unsubscribe from this community discussion, go to
https://community.culturalheritage.org/HigherLogic/eGroups/Unsubscribe.aspx?UserKey=d16eaa87-0f69-494b-9f2f-303dbc1222e1&sKey=fab9aa4f27a04c5d876e&GroupKey=757a8f16-505f-4323-8e74-e376757aa9f7.
