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(Book and Paper) It All Comes out in the Wash, or Does it? A Comparative Study of Washing Treatments on a Group of 18th Century Engravings by Grace Walters, Sylvia Albro, Julie Biggs, Claire Dekle, Claire Valero, and Tana Villafana

By Stacey Kelly posted 06-02-2019 17:10

  
Link to abstract:
https://aics47thannualmeeting2019.sched.com/event/Iufj

Presenter: Grace Walters
By: Grace Walters, Sylvia Albro, Julie Biggs, Claire Dekle, Claire Valero, and Tana Villafana

This talk compared three different washing protocols on nine 18th-century black and white engravings at the Library of Congress. The aims of the washing treatment were to reduce staining, overall discoloration, and acidity in the prints. The methods were evaluated based on  results of the treatment, and the practical advantages and disadvantages of the various treatment methods. The prints were documented with digital photography, UV-induced visible fluorescent imaging, and reflectance spectroscopy (FORS). Comparative readings of the brightimeter (a TAPPI standard) and the FORS were undertaken by the authors, both readings showed results in comparative range.

The three treatment methods tested were:
All the prints were humidified and misted with 50:50 water: ethanol solution before washing

three treatment methods
1. Rigid Polysaccharide Gel
- A 2% Gellan Gum gel was used with Hanji paper as a barrier layer. Felts were used as a weight; gel applied for 2 hours
- A subsequent gel was placed without a barrier layer for 1.5 hours, no discoloration was seen in the gel after that time period

2. Immersion in adjusted chelating solutions
- 6 different solutions were tested using agarose plugs applied to the surface of the print for 5 min and covered with mylar; tidelines formed
- Chelating solutions C and D showed good results. The final solution chosen was added to a bath of deionized water until the bath resulted in a conductivity approximately 5x that of the object
- Two rinse baths of deionized water was used to rinse the object after immersion with the chelating solution

Chelating solutions 

Recipes

Solution A

100ml H2O (distilled)
0.5g Citric Acid
Adjust pH to 6.0 with 50% w/v 1M NaOH solution

Solution B

100ml H2O (distilled)
0.5g Citric Acid
0.5g Tetrasodium Borate
Adjust pH to 8.0 with 50% w/v 1M NaOH solution

Solution C

100ml H2O (distilled)
0.5g DTPA
O.5g Citric Acid
Adjust pH to 6.0 with 50% w/v 1M NaOH solution

Solution D

100ml H2O (distilled)
0.5g DTPA
0.5g Tetrasodium Borate
Adjust pH to 8.0 with 50% w/v 1M NaOH solution

Solution E

100ml H2O (distilled)
0.5g Disodium EDTA
0.5g Citric Acid
Adjust pH to 6.0 with 50% w/v 1M NaOH solution

Solution F

100ml H2O (distilled)
0.5g Disodium EDTA
0.5g Tetrasodium Borate
Adjust pH to 8.0 with 50% w/v 1M NaOH solution

Note: These solutions were a result of workshops held by Richard Wolbers at the Library of Congress in 2014 and 2016. 

3. Immersion in conditioned water
- pH adjusted water to 7.5 (3 x 20 min baths)


Results:

  • All three methods were effective in increasing the improving the brightness and visual appearance of the prints
  • Tidelines from the agarose plugs remained visible under UV illumination which could lead to long-term differential ageing of those areas
  • Options 1 and 2 require more preparation, time and equipment


Rigid Polysaccharide Gel

Immersion in adjusted chelating solutions

Immersion in conditioned water

- Gel is easy to make

Sheets can be made in advance – check for microbial growth before use

Does not require a sink

Size of the artwork can be a limiting factor

Agarose plugs must be prepared ahead of time

Treatment bath must be prepared and calculated once testing has occurred

Expensive chemicals

Tidelines formed during testing needs further investigation

- Simple preparation

Does not require a sink

Not recommended for friable or soluble media


Questions from the audience:

  1. Why place a barrier for the Gellan gel during the first application and not the second? This was done as a study for the team to dry different applications.
  2. What was the temperature of the washing solutions? Room temperature.

Stacey M. Kelly
Paper Conservator
U of Utah, J. Willard Marriott Library
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