RESCUE OF ACIDIC PAPER
IN LIBRARY AND ARCHIVAL COLLECTIONS
Mass deacidification in practice
Ing. Petra Vávrová, Ph.D., independent freelance conservation scientist
NLA 2026 | Heritage Preservation for a Sustainable Future images built with ChatGPT.
The preservation problem
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NLA 2026 | Heritage Preservation for a Sustainable Future
Ing. Petra Vávrová, Ph.D.
Acid hydrolysis shortens cellulose chains
Paper loses folding endurance before it loses information
Lignin-rich wood pulp can accelerate yellowing and acid formation
Heat and moisture increase reaction rates
Once paper becomes brittle, deacidification cannot restore lost strength
Best intervention window
Acidic paper that still retains enough mechanical strength for handling
What deacidification changes
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NLA 2026 | Heritage Preservation for a Sustainable Future
Ing. Petra Vávrová, Ph.D.
TREATMENT
Neutralises acids
The alkaline agent reacts with acids already present in the paper.
Adds an alkaline reserve
Residual alkaline material helps counter acids formed later or introduced from the environment.
LIMIT
Does not strengthen brittle paper
Deacidification slows further acid hydrolysis. It does not reconnect broken cellulose chains or repair bindings.
Treat before embrittlement
becomes advanced
Selecting a treatment method
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NLA 2026 | Heritage Preservation for a Sustainable Future
Ing. Petra Vávrová, Ph.D.
The collection defines the method
BOUND VOLUMES
Non-aqueous systems are commonly used because they reduce swelling and deformation of book structures.
Check
Solubility of inks and media
Binding materials and attachments
Dimensions and chamber limits
LOOSE SHEETS AND RECORDS
Aqueous and non-aqueous options may be considered. Housing, media and desired handling properties guide the choice.
Compare providers by measurable outcomes
pH and alkaline reserve
Distribution through the sheet or text block
Side effects and reproducibility
Candidate selection
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NLA 2026 | Heritage Preservation for a Sustainable Future
Ing. Petra Vávrová, Ph.D.
A good candidate is acidic, valuable and still usable
PRIORITISE
Paper with low pH and sufficient strength
High research, cultural or evidential value
Frequently used or irreplaceable holdings
Coherent batches with reliable catalogue data
EXCLUDE OR REVIEW
Paper already too brittle for safe handling
Unstable or soluble media
Mould, active pests or water damage
Complex attachments, coated papers or incompatible bindings
Mass deacidification workflow
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NLA 2026 | Heritage Preservation for a Sustainable Future
Ing. Petra Vávrová, Ph.D.
1
Survey
Define priorities and exclusions
2
Pilot
Test a representative batch
3
Prepare
Collate, document and pack
4
Treat
Process under controlled conditions
5
Verify
Measure results and side effects
6
Return
Update records and improve storage
Decision gates belong before and after treatment. A rejected item must remain traceable and return to the correct shelf or conservation route.
Preparing books for treatment
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NLA 2026 | Heritage Preservation for a Sustainable Future
Ing. Petra Vávrová, Ph.D.
Preparation prevents avoidable damage and lost context
01
Identify
Barcode or shelfmark, batch list, treatment status
02
Collate
Check pagination, loose leaves and inserted material
03
Stabilise
Secure minor loose parts only within the agreed protocol
04
Flag risks
Media, labels, photographs, coated leaves, unusual bindings
05
Document
Condition photographs
and concise exception notes
06
Pack
Support volumes,
control orientation
and record container order
Treatment at scale
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NLA 2026 | Heritage Preservation for a Sustainable Future
Ing. Petra Vávrová, Ph.D.
A controlled industrial process
Books or records enter a treatment chamber
A deacidifying agent reaches the paper under controlled conditions
The reagent neutralises acids and leaves an alkaline reserve
Conditioning removes process residues and restores handling equilibrium
The provider must document process parameters, exclusions and acceptance limits.
Quality control before treatment
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NLA 2026 | Heritage Preservation for a Sustainable Future
Ing. Petra Vávrová, Ph.D.
A pilot establishes the baseline and acceptance criteria
Representative sample
Paper types, dates, formats, inks, bindings and condition groups
Baseline measurements
Surface or cold-extraction pH where appropriate, alkaline reserve, colour and mechanical indicators
Visual record
Text block, covers, labels, stamps, media and existing distortions
Decision rules
Minimum result, tolerated variation, rejection criteria and responsibility for damage
Post-treatment evaluation
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NLA 2026 | Heritage Preservation for a Sustainable Future
Ing. Petra Vávrová, Ph.D.
Verify chemical performance and practical usability
CHEMICAL
pH increase
Alkaline reserve
Distribution and consistency
PHYSICAL
Colour and odour
Distortion or blocking
Handling and page turning
DOCUMENTARY
Batch reconciliation
Exceptions and damage
Permanent treatment record
Compare like with like: the same method, conditioning and measurement location.
Limits and risk management
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NLA 2026 | Heritage Preservation for a Sustainable Future
Ing. Petra Vávrová, Ph.D.
Mass deacidification slows one major degradation pathway. It does not replace conservation treatment, good storage, safe handling or disaster preparedness.
Material response
Possible colour, surface, odour, dimensional or media changes
Uneven uptake
Different papers and book structures may receive different deposits
False security
A treated book can still fail through handling, heat, moisture, mould or poor housing
Evidence loss
Removing inserts or altering labels without documentation can destroy context
A sustainable programme
Treat the right material
before it becomes brittle
Define measurable acceptance criteria
and preserve the treatment record
Mass treatment gains value when it connects selection, conservation science and long-term collection care.
Thank you | petulavavrova@centrum.cz
Ing. Petra Vávrová, Ph.D.