Preserving Your Past

  • preservation of old photod

When undertaking any kind of preservation treatment, live by this rule:

The treatment should be reversible.

Common sense approach – always start with the least invasive treatment but if you aren’t sure what to do, don’t do anything. Instead, contact the McHenry County Historical Society.

Factors that lead to damage
Pollution: avoid storage containers that off-gas. Avoid dust which is abrasive. Avoid unsealed wooden shelving which off-gases. The more aromatic the wood, the more off-gassing it is.

Pests: silverfish, moths, rodents. Remember, most antique textiles are composed of self-destructing natural fibers. Wood and silk are animal-based and cotton and linen are plant-based. Also note that up to about 1850 paper was made of cotton, hemp, linen or mulberry fibers. It was referred to as rag paper. After the mid 19th century, wood fibers which were acidic made up the bulk of paper products resulting in a poorer quality paper.

Temperature: avoid rapid fluctuations in temperature and humidity. 50° - 68° for photographs with fluctuations of no more than 5 degrees per day. Cold storage at low relative humidity is ideal. 60° - 65° for textiles.

Relative Humidity: wood, leather, paper, and textiles respond to fluctuations in moisture by expanding and contracting. Ideal relative humidity for photos is between 35° - 40°. The ideal RH for textiles and paper is 50°.

Light levels: damage caused to artifacts by light is cumulative and irreversible.
1. Most sensitive to light – textiles and other dyed fibers, dyed leather, fur and feathers, manuscripts on parchment, prints and drawings on paper, water colors, stamps, color photographic prints and transparencies, historic plastics.

2. Moderately sensitive to light – oil and tempera paintings, lacquer ware, wood, horn, bone, ivory, black and white photographs, some colored glass.

3. Insensitive to light – stone, metal, most glass, ceramics.

Careless handling.


Preservation Resources

Archival supplies and technical product advice

Gaylord – Library supplies, furniture and archival products, 800-448-6461

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