44th Annual Meeting – Photographic Materials Session, May 16, "Separation Anxieties: Freeing photos adhered to glazing or to each other" by Barbara Lemmen and Emma Lowe

Title image
This talk was split into two sections, beginning with a presentation by Emma Lowe examining the nature of the adhesive bond formed between blocked photographic prints (prints stuck together in a block) and glazing. This was then followed by Barbara Lemmen providing an overview of existing treatments used by photo conservators to tackle this issue.
The Experiment
Lowe’s research aimed to assess the nature of a blocked bond, and determine the factors that affect the bond e.g. surface finish, glass coatings, age of the bond.
She tested artificially aged samples of both glossy and matt prints adhered to three different types of glass including glass with no coating, glass with UV surface coating, and glass with integral optical coating. Half the samples were aged for 80 days, the others for 150 days at 30°C (86°F) and 50% RH.

Blocked glossy and matt DOP samples
Blocked glossy and matte DOP samples

Experiment Results
At 80 days, it was found that all the samples could be popped off the glass. At 150 days, 75% of the samples tore upon removal; glossy prints were even more likely to tear than matte samples.
XRF analysis of the gelatin layer pre and post-experiment showed that there was migration of the elements in and out of gelatin. At 80 days, there was a slight increase in Si in matte samples. At 150 days, there were changes in elemental composition. FTIR showed compositional changes in gelatin and glass pre and post experiment. SEM/EDS on cross sections of the artificially blocked samples showed the migration of elements across the blocked bond. Changes in elemental composition were seen within the gelatin colloid.
In short, Lowe’s experiment determined the following points:

  • The initial adhesion between matte finished prints to glass is stronger, but aging leads to a stronger bond between glossy finished prints and uncoated glass.
  • UV coating on glass acts as a barrier to adhesion
  • There is a migration of materials between 80 – 150 days; electrostatic attraction between the glass and print converts to a covalent bond, explaining the increased bond strength. At 80 days 100% of samples separated without damage, at 150 days 75% of samples tore from the glass.

Treatment Overview
Lemmen then presented a variety of techniques used for the separation of photographs from glazing or blocked prints. For prints on glass (depending on the sensitivities of the object), the introduction of heat or moisture allows the gelatin to swell; this can be done via local humidification, the targeted application of aqueous solutions, steam or immersion (less common). Mechanical methods include removing the object from glass with a blade, or breaking the glass using a glass cutter.  Dry heat or freezing with dry ice can also be used as a form of separation.
Blocked prints can be peeled apart mechanically, or they can be swelled with moisture. While trying to peel the sections apart, the local application of aqueous solutions to the adhered areas can aid separation. Overall humidification can be done on fiber base only. Splitting the RC prior to immersion was also discussed. 

Immersing RC prints
Immersing RC prints

what works reliably
Treatment options for fiber base and RC prints

In conclusion, it was recommended to prioritize treatment of prints adhered to glass. In the occasion where prints need to be framed without a window mat or spacer, use UV filtering glass face-in to reduce the possibility of adhesion.

44th Annual Meeting – Luncheon Session, May 15, Emerging Conservation Professionals Network Luncheon

The emerging conservation professionals luncheon was one of the events I was really looking forward to at the annual meeting. As a recent graduate and having just entered the conservation field as a postgraduate fellow, the idea of having a chance to converse with established conservation professionals, and receive advice to help launch my own career was extremely appealing.
Prior to the event, participants filled in a short online form that established what we wanted to achieve from the session. We could sign up as a mentor or a mentee, and choose between a variety of interests including (but not limited to) networking, jobs and fellowships, resume writing, getting into conservation and so on. This information was then used to match us to the people we would be interacting with during the session.
At the luncheon, participants were grouped into tables with approximately 7 – 8 people. At my table were two established conservation professionals, three recent graduates with fellowships/jobs, and two others new to the field.
The program started with an overview of the ECPN, introducing their board members, goals, and previous and upcoming programming. This was useful to new participants, allowing them to know who to reach out to, as well as the resources available to them. This was followed by several testimonials from established professionals, including Sarah Melching, Director of conservation at the Denver Art Museum who gave an in depth account of her unconventional pathway into conservation. It was interesting and also served as a source of encouragement for pre-program attendees.
Once the organized talks were completed, the official networking session began. Each table had a list of questions to facilitate discussions, making it easier for those of us who are a little shyer to keep the conversation flowing. The diversity at the tables was interesting, allowing some who came as mentees to serve as mentors to those just entering the field. This was surprising, yet rewarding. Personally, I left the event knowing I made some new connections, connections that only got stronger throughout the course of the conference.
I hope that such opportunities continue to be offered at future AIC meetings. The support provided from established colleagues in the field is invaluable and I find myself wishing that more time had been devoted to the mentor-mentee exchange. I would also appreciate the prospect of meeting more mentors and talking to them on a one-on-one basis. Thank you ECPN and ECC for organizing the event!
To find out more about the ECPN network and their resources, visit their page here.