Connecting to Collections Care

Hi Nikki,

As the acting C2C Care community monitor, I'd like to thank you for posting this question to the community. Relative humidity may be playing a role in the appearance of spotting. Other avenues of investigation would be pollutants from exhibit case construction materials/components and the production method of the glass object in question. Could residual processing agents on the glass be interacting with pollutants associated with exhibit case materials? How would RH affect possible pollutants or residues?

I've included Stephen P. Koob's article Cleaning Glass: a many faceted issue, which offers an explanation of weeping/crizzling, ways to mitigate development, and environmental considerations for storing and displaying glass. 

https://resources.culturalheritage.org/wp-content/uploads/sites/8/2015/02/osg011-05.pdf

Caring for Glass Collections: The Importance of Maintaining Environmental Controls, also by Stephen P. Koob, may be helpful in answering some of your questions. Unfortunately, I currently do not have access to the full article.

As always, community members are encouraged to share experiences, advice and resources.

Original Message:
Sent: 03-04-2025 13:33
From: Nikki Gough
Subject: Glass Hazing and brown spots

Hi Everyone, 

I was checking on some pieces we have currently on exhibit and noticed that this glass sculpture which went on exhibit in excellent condition last year, is now showing some signs of damage. For some background, the piece was made in 2021, which we purchased for our collection. It has been in storage until last year. It is on display in an enclosed large display case with motion censored lighting. The conditions in the case as ok, its an old exhibit and often has low humidity levels but temperature is fine. Below I included some pictures of the various issues I found within the glass sculpture. I found three new developments, hazing, brown spots, and white spots.

Above is an image of the brown spotting I found on this glass piece. The spotting is all over the interior side of the piece. The interior is where the etching was done and the brown spotting is found in the etching cracks. The brown areas did not come off with a damp cloth of water or glass cleaner. I included a close up image of the brown spotting as well. I was not able to find any current articles about what this could be.

The above image is from the same piece of glass on the interior side. The piece now seems to have a line of hazing that does not come off with water or glass cleaner. I have read a bit about hazing and understand that it will not come off of the piece but I would love a further explanation of why the hazing appeared while on exhibit. 

The image above depicts white spotting located on the second glass piece. The white spotting is found throughout the interior etched side of the glass. The white spotting is always in the cuts of the etching. The white spots were cleaned with a damp cloth of water and glass cleaner, they left but quickly came back. I am aware of this phenomenon happening with glass beads that have glass bead disease (more of a haze than spotting) but not with glass in this form. 

I would really appreciate any help with understanding why these issues are happening with the glass sculpture and if there is anything I can do to mitigate it from happening again or to prevent these problems from getting worse. 

I know this is a lot in one post but thank you in advance for any guidance or help!

------------------------------
Nikki Gough
Collections Manager
High Desert Museum
Bend
United States
------------------------------

Hi Sharon, 

I think humidity is playing a big role in the spotting. The case construction and materials are very old so I wouldn't be surprised if they were also a contributing factor to possible pollutants.

Thank you for the article, that is a very helpful resource. It does seem after reading that this is the beginning stages of weeping glass. I will take the glass basket off exhibit so it is in a more stable environment.

I appreciate the help!

Original Message:
Sent: 03-05-2025 10:47
From: Sharon Fickeissen
Subject: Glass Hazing and brown spots

Hi Nikki,

As the acting C2C Care community monitor, I'd like to thank you for posting this question to the community. Relative humidity may be playing a role in the appearance of spotting. Other avenues of investigation would be pollutants from exhibit case construction materials/components and the production method of the glass object in question. Could residual processing agents on the glass be interacting with pollutants associated with exhibit case materials? How would RH affect possible pollutants or residues?

I've included Stephen P. Koob's article Cleaning Glass: a many faceted issue, which offers an explanation of weeping/crizzling, ways to mitigate development, and environmental considerations for storing and displaying glass. 

https://resources.culturalheritage.org/wp-content/uploads/sites/8/2015/02/osg011-05.pdf

Caring for Glass Collections: The Importance of Maintaining Environmental Controls, also by Stephen P. Koob, may be helpful in answering some of your questions. Unfortunately, I currently do not have access to the full article.

As always, community members are encouraged to share experiences, advice and resources.

------------------------------
Sharon Fickeissen
Connecting to Collections Care Monitor
Senior Library Conservation Technician
Hagley Museum & Library
Wilmington DE
sfickeissen@hagley.org

Original Message:
Sent: 03-04-2025 13:33
From: Nikki Gough
Subject: Glass Hazing and brown spots

Hi Everyone, 

I was checking on some pieces we have currently on exhibit and noticed that this glass sculpture which went on exhibit in excellent condition last year, is now showing some signs of damage. For some background, the piece was made in 2021, which we purchased for our collection. It has been in storage until last year. It is on display in an enclosed large display case with motion censored lighting. The conditions in the case as ok, its an old exhibit and often has low humidity levels but temperature is fine. Below I included some pictures of the various issues I found within the glass sculpture. I found three new developments, hazing, brown spots, and white spots.

Above is an image of the brown spotting I found on this glass piece. The spotting is all over the interior side of the piece. The interior is where the etching was done and the brown spotting is found in the etching cracks. The brown areas did not come off with a damp cloth of water or glass cleaner. I included a close up image of the brown spotting as well. I was not able to find any current articles about what this could be.

The above image is from the same piece of glass on the interior side. The piece now seems to have a line of hazing that does not come off with water or glass cleaner. I have read a bit about hazing and understand that it will not come off of the piece but I would love a further explanation of why the hazing appeared while on exhibit. 

The image above depicts white spotting located on the second glass piece. The white spotting is found throughout the interior etched side of the glass. The white spotting is always in the cuts of the etching. The white spots were cleaned with a damp cloth of water and glass cleaner, they left but quickly came back. I am aware of this phenomenon happening with glass beads that have glass bead disease (more of a haze than spotting) but not with glass in this form. 

I would really appreciate any help with understanding why these issues are happening with the glass sculpture and if there is anything I can do to mitigate it from happening again or to prevent these problems from getting worse. 

I know this is a lot in one post but thank you in advance for any guidance or help!

------------------------------
Nikki Gough
Collections Manager
High Desert Museum
Bend
United States
------------------------------