Stopping Time: The Art of Encapsulation
Many years ago, lamination was widely viewed by the general public as an effective and sustainable preservation method. It was believed that laminating paper documents would shield them from climate fluctuations, mold, and human touch, preserving fragile items for future generations.
Unfortunately, time has proven that lamination causes far more harm than good.
Lamination is neither permanent nor chemically neutral, and it fails to offer true protection. Over time, the plastic layers separate, allowing polluted air, moisture, and pests to penetrate—eventually crumbling the item to dust. Even worse is the lamination adhesive itself: it dissolves inks, absorbs deeply into paper fibers, causes irreversible discoloration, and damages the document permanently.
Surprisingly, even today—decades after the severe damage caused by lamination has been scientifically proven—many framing and print shops still erroneously recommend lamination to their clients as a "preservation technique."
How Do We Preserve Important Documents Correctly?
Modern conservators operate under a strict code: never perform an irreversible action on archival items, historical documents, or works of art.
Instead of lamination, professional conservators use a technique called Encapsulation.
The Encapsulation Process
- Decontamination & Sterilization: The item undergoes treatment to eliminate active mold spores and microscopic pests (such as booklice and silverfish). Depending on the materials, techniques may include controlled evaporation, irradiation, or anoxia (oxygen deprivation).
- Restoration & Stabilization: If necessary, the item undergoes conservation treatment first—such as tear mending, cleaning, and structural stabilization.
- Enclosure: The document is placed between two sheets of archival-grade polyester film (such as Mylar or Melinex). It is typically held in place naturally by the electrostatic charge generated between the sheets.
- Climate Conditioning: The enclosure is prepared in an environment conditioned to 45% Relative Humidity (RH) following a 12-to-24-hour equilibration period. This ensures mold cannot develop (mold generally requires RH above 60% to grow).
- Sealing: If the item will be stored without full climate control, the edges of the polyester are sealed, creating a safe, localized microclimate that protects the document from external hazards.
Because archival polyester is rigid yet highly flexible and crystal clear, even extremely fragile items—such as brittle vintage newspaper clippings—become safe to handle, inspect, photograph, and transport.
Key Advantages & Important Considerations
- 100% Reversible: Encapsulation is completely non-invasive. If the document ever needs to be removed, conservators simply trim the outer polyester edges, releasing the item completely unharmed.
- Chemically Inert: Archival polyester is acid-free and chemically stable—it will not react with or degrade the paper over time.
- Long-Term Storage Only: Encapsulation is designed primarily for flat archival storage, not for hanging display, rolling, or folding.
When Encapsulation Should NOT Be Used:
Because encapsulation relies on static electricity, it is unsuitable for friable (powdery) media such as charcoal, pastel, or soft chalk. Static charges can pull pigment particles off the paper. For powdery media, the proper method is storing the item in a standard acid-free paper folder within a climate-controlled environment.
Essential Technical Warnings
The "Mini-Greenhouse" Effect
Encapsulation can trap internal heat if stored in warm environments subject to rapid temperature swings. This heat can accelerate acid hydrolysis—a process where intrinsic acids within the paper (such as those in Iron Gall Ink or wood-pulp papers) break down the fibers faster.
The Solution: Prior to encapsulation, documents should ideally undergo deacidification. Alternatively, conservators place an alkaline barrier paper (pH 8+ containing 3–5% calcium or magnesium carbonate) behind the document inside the capsule to continuously neutralize acids over time.
Archival Ventilation
When encapsulated items are kept in certified archival storage facilities with strict environmental controls (45%–50% RH, constant temperature, and air filtration), conservators often notch or clip the corners of the polyester sheet to allow the document to "breathe."
By Michael Karov Karo
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