Care of Basketry – Canadian Conservation Institute (CCI) Notes 6/2
Introduction
Baskets, mats, woven hats, and similar objects composed of plant materials were originally made to be used everyday — which meant they were exposed to light, heat, humid or dry conditions, and physical stress. As a result of this use, these artifacts are often weak and brittle. Although they may appear to be durable, they can easily be damaged. Care in handling, display, and storage is essential.
Handling
Poor handling is one of the major causes of damage to basketry. Never lift baskets by the rims or handles. These once strong areas may have become severely weak and embrittled, and serious damage can result from this kind of improper handling. Use both hands to carry any object, and support it at its base. Use padded trays and trolleys to move objects.
Storage
Basketry should be stored in the dark, as it is sensitive to light. Most dyed elements are particularly light-sensitive.
Support fragile objects or unusual shapes by lightly filling them with unbuffered, acid-free (neutral pH) tissue paper, adding outer supports such as shaped polyethylene foam blocks (e.g. Ethafoam), or a donut-shaped circular support made of medical stockinette stuffed with polyester fibrefill. Ensure that any materials in contact with basketry are acid-free to avoid contributing to further chemical deterioration.
Do not store small objects inside larger ones, as this can easily cause damage. If storage in this manner is unavoidable due to space limitations, separate each piece with unbuffered acid-free (neutral pH) tissue paper. Overcrowding can cause compression damage, deformations, kinks, tears, and breakage. Therefore, when planning and designing your storage area, it is important to allocate enough room for all items in your care.
If fibres or elements have become detached through handling, record their loss, place them in a labelled, clear plastic ziplock bag, and store them with the artifact. Protruding fibres in danger of catching on adjacent objects can be tied down gently with white or colourfast cotton thread or fabric tape. Never use monofilament fishing line for this purpose, as it can easily pull and cut through fragile basketry fibres.
Make periodic checks (twice annually at a minimum) for insect infestations, as insects can damage a collection quickly. Information on biological infestation can be found in CCI Notes 3/1 Preventing Infestations: Control Strategies and Detection Methods and 3/2 Detecting Infestations: Facility Inspection Procedure and Checklist. Immediate attention is required if an infestation is detected. Contact the Canadian Conservation Institute for advice.
Additional information on storage guidelines can be found in CCI Notes 1/1 General Precautions for Storage Areas.
Dust
When objects are in storage, protect them from dust through a combination of good housekeeping and the use of closed cabinets or dust covers over open shelves. When objects are on display, use closed cases. Dust can be abrasive and, depending on dust components, can react with moisture to accelerate chemical degradation or provide nutrition for insects and mould. Dust will also be unsightly and hide surface detail, and become increasingly difficult to remove the longer it is allowed to accumulate.
Cleaning
It should first be noted that what appears as "dirt" may in fact be evidence of previous use. Deposits such as seeds, berry stains, etc. are part of the object's history of use and should under no circumstances be removed. Cleaning is an irreversible process so care must be taken to remove only what is necessary.
Begin by placing the object on a clean table. With a soft brush, dislodge dust and debris, directing it toward a gauze/screen-covered vacuum cleaner nozzle. The screen acts as a filter for any detached fibres or decorative additions lifted off the object. If possible, use a vacuum (HEPA filter suggested) with power reduction controls to easily reduce the suction. If your vacuum does not have these controls, open the suction control and use an attached tube with perforations to reduce suction at the nozzle.
Disfiguring surface dirt that cannot be removed with a brush and vacuum can possibly be reduced with a sponge-like rubber eraser known as a "dry-cleaning" or "chemical" sponge. Used dry, it is usually sold in a brick-sized shape but can be cut into smaller pieces. Often the end of a triangular shape allows access along woven materials. Gently rub the dirty area, noting if any fibres are removed and if the sponge removed any dirt. If dirt is removed without damaging the basketry, continue cleaning, repositioning the sponge as needed to obtain a clean surface.
A soft kneadable eraser, Groomstick, is slightly sticky and will pick up loose particles. Touch a small piece to the dirty area, or wrap a small piece around a toothpick or skewer and roll the end over the surface to collect dirt. The soiled eraser can be kneaded and re-used until it is no longer sticky, at which time it should be discarded.
As with any cleaning method, the operator has great influence over the result and the effect on the basket. Gentle pressure is required to avoid compressing or lifting basket fibres. Always test an eraser on a small area first to ensure it removes only what you want to remove. If the surface of the basket is friable or any applied decoration is not well attached, the method may not be suitable.
Ingrained dirt can sometimes be removed with a cotton swab barely dampened with water. However, before cleaning an artifact in this manner, test the treatment in an inconspicuous area. After wetting a cotton swab with distilled water, blot it on a paper towel to ensure it is not too wet, and then roll it gently over the surface of the test area. Allow the area to dry and determine if the cleaning was effective and if the object tolerated the cleaning process without damage. Be sure to test all colours before conducting an overall treatment, and do not over-dampen the surface as this may cause differential shrinkage or expansion. Never immerse basketry in water.
If the methods described above are not suitable or effective, consult a conservator for additional suggestions.
Repair
Basketry that is damaged should be referred to a conservator before any repair is attempted. Irreparable damage can occur as a result of an uninformed choice of materials or method. Please contact the Canadian Conservation Institute for advice.
Illumination
Damage due to light is cumulative and irreversible. Some of the dyes used on basketry are among the most light-sensitive materials found in museum collections. Unless dyed objects were carefully protected from light, it is expected that some fading has occurred. Basketry artifacts, whether dyed or not, should therefore be displayed at low light levels to reduce deterioration. Protect objects from light when they are not being viewed: turn off lights in storage areas and keep light levels as low as possible when on display. For dyed basketry, 50 lux with below 75 µW/lm of ultraviolet (UV) radiation is recommended to keep light damage to a minimum. Displaying undyed basketry at slightly higher levels, 100 or 150 lux, can be considered. Reducing the exposure time will also reduce damage. Further information concerning the measurement of light levels and UV filtration can be found in CCI Notes 2/4 Environmental Monitoring Kit (retired) and 2/1 Ultraviolet Filters. See also Light, Ultraviolet and Infrared.
Relative Humidity (RH) and Temperature
RH and temperature are factors in the safe long-term storage and display of basketry. RH over 65 % can promote mould growth, and RH below 40 % can lead to increased desiccation and embrittlement. For unrestrained components of basketry, lower RH levels alone may not contribute to the deterioration of plant materials. However, because the plant parts become more brittle, the objects will require greater care when handled. For basketry in which the plant fibres are tightly constricted against a rigid material, low RH and fluctuations in RH that lead to expansion and contraction of the fibres can cause damage to the object.
High temperatures can accelerate embrittlement of basketry due to potentially drier air, and raise the rate of chemical deterioration. A temperature below 25 °C is recommended. Be aware that the radiant heat from direct sunlight or bright spotlights can raise the temperature within a display case, or heat the surface of basketry on open display. To prevent this problem, maintain low light levels and use lights that emit less radiant heat.
Suppliers
Note: The following information is provided only to assist the reader. Inclusion of a company in this list does not in any way imply endorsement by the Canadian Conservation Institute.
Unbuffered, acid-free (neutral pH) tissue paper:
- Conservation product suppliers such as:
Ethafoam:
- DuPont Global Headquarters (manufacturer)
- Poly Foam Products Ltd.
Telephone: 905-678-0820 - Renovation centres, hardware stores, and craft suppliers
Medical stockinette:
- Medical suppliers
Dry-cleaning/chemical sponge:
- Conservation product suppliers
Kneadable eraser (e.g. Groomstick):
- Conservation product suppliers
Bibliography
Florian, M.-L., D.P. Kronkright, and R.E. Norton. The Conservation of Artifacts Made from Plant Materials. Marina del Rey, CA: The Getty Conservation Institute, .
Ogden, S., editor. Caring for American Indian Objects: A Practical and Cultural Guide. St. Paul, MN: Minnesota Historical Society Press, .
by staff of the CCI Objects Conservation Lab
Originally published
Revised ,
Copies are also available in French.
Texte également publié en version française.
©Minister of Public Works and Government Services Canada,
Cat. Nº NM 95-57/6-2-2010E
ISSN 0714-6221
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