Table 3 is a list of recommended environmental conditions for the storage, display and transport of museum objects. Though it may be difficult for a museum to achieve these 'ideal' standards, the best possible conditions within the limitations should prevail. In all cases, the emphasis should be on achieving stable levels of temperature and relative humidity (RH), minimum light levels and elimination of all UV light. In some instances the maximum light level of 300 lux is reasonably low for the material, however it is rarely necessary to exceed this.
The table is organised by materials (ie wood, clay, metal etc) rather than object type (ie machinery, clothing, book). When using the table in relation to objects made from two or more materials, the recomŽmendations for each material should be checked and the narrowest range of temperature and RH, lowest level of lux and mw/lumen and the shortest display period should be taken as the 'ideal' conditions for the whole object.
For example, if you have you have a metal bicycle with a leather seat, rubber tyres and some plastic components, you would assess the categories in Table 1. In comparing the requirements of each material, you will see that the plastic and rubber components have the narrowest range of tolerance in all categories and hence will dictate the environmental conditions.
| Material | Temperature | Relative humidity (RH) | Max light (lux) | Max UV wm/lumen | Max display period per 12 months |
|---|---|---|---|---|---|
| Leather | 20 ± 2°C | 50 ± 10% | 50 (dyed) 200 (undyed) | 30 (dyed) 80 (undyed) | 3 months 6 months |
| Metals (not specified elsewhere) | 20 ± 2°C | < 35% | 300 | unrestricted | unrestricted |
| Plastic (not specified elsewhere) | 20 ± 2°C | 50 ± 10% | 50 (display) Nil in storage | 30 (display) Nil in storage | 3 months |
| Rubber (soft) | 20 ± 2°C | 50 ± 10% | 50 (display) Nil in storage | 30 (display) Nil in storage | 3 months |
Another example is a painting that may be painted in oil on a gessoed canvas, stretched on a wooden strainer/stretcher with a composition gesso and gilt frame. When assessing the painting by comparing the requirements of each material (Table 2), it will be clear that most of the components have a similar but inconsistent range of tolerance. The lowest tolerance in each section should form the ideal environmental conditions for the whole object.
| Material | Temperature | Relative humidity (RH) | Max light (lux) | Max UV wm/lumen | Max display period per 12 months |
|---|---|---|---|---|---|
| Canvas | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months |
| Composition (Compo; as used on frame mouldings) | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months |
| Gesso | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months |
| Gold (include leaf & gilt) | 20 ± 2°C | < 35% | 300 | unrestricted | unrestricted |
| Oil paint | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months |
| Wood (not specified elsewhere) | 20 ± 2°C | 50 ± 5% | 200 | 80 | 6 months |
| Material | Temperature | Relative humidity (RH) | Max light (lux) | Max UV wm/lumen | Max display period per 12 months | Prone to insect &/or mould attack | Other Considerations |
|---|---|---|---|---|---|---|---|
| Acrylic paint | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | If paint is thin, treat as if watercolour. Paint embrittles with age. | |
| Acrylic plastics (ie perspex) | 20 ± 2°C | 50 ± 10% | 300 | 200 | 9 months | Certain chemicals may cause crazing. | |
| Alabaster | 20 ± 2°C | 50 ± 10% | 300 | unrestricted | unrestricted | Soluble in weak acids and prone to attack by organic acid vapours. | |
| Amber | 20 ± 2°C | 50 ± 10% | 300 | 200 | unrestricted | Brittle: cracks or breaks easily. Soluble in many organic solvents. | |
| Bakelite and Catalin | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Discolours with age. | |
| Baleen | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | |
| Bamboo | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Yes | |
| Bark | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Yes | Hygroscopic - will crack, warp etc in fluctuating RH. |
| Beadwork | Yes | Beads are constructed from many different materials and should be assessed on a case by case basis. | |||||
| Bitumen | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Prone to dust and dirt accumulation. Can creep prior to drying (20 yrs) and cracks on drying. | |
| Bone | 20 ± 2°C | 45 - 65% | 200 | 80 | 6 months | Yes | Hygroscopic - will crack, warp etc in fluctuating RH. Prone to staining. |
| Bone china | 10-30°C | 20 - 60% | 300 | 200 | unrestricted | Repair materials (adhesives, fillers, paint etc) may require lower light levels and restricted display periods. | |
| Brick | 20 ± 2°C | 50 ± 10% | 300 | unrestricted | unrestricted | Repair materials (adhesives, fillers, paint etc) may require lower light levels and restricted display periods. | |
| Camphorwood | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | *Yes | Hygroscopic - will crack, warp etc in fluctuating RH. * Mature wood is resistant to insect attack. |
| Cane | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Yes | Tends to embrittle with age. |
| Canvas | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Yes | Collects dust easily. |
| Cardboard | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | Discolours and embrittles with age. Most cardboard made post 1850 is inherently acidic. |
| Cast iron | 20 ± 2°C | <35% | 300 | unrestricted | unrestricted | May have a soft graphitised section which is prone to physical damage. Protective coating system may require lower light levels and restricted display periods. | |
| Casein | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Yes | Prone to drying (crazing) in RH below that recommended. Wax coating will minimise drying. Discolours and embrittles with age |
| Cedar (Australian) | 20 ± 2°C | 50 ± 5% | 200 | 80 | 6 months | *Yes | Hygroscopic - will crack, warp etc in fluctuating RH. * Mature wood is resistant to insect attack. |
| Ceramic (not specified elsewhere) | 10-30°C | 20 - 60% | 300 | 200 | unrestricted | Repair materials (adhesives, fillers, paint etc) may require lower light levels and restricted display periods. | |
| Cellulose acetate and cellulose nitrate films | <15°C | 22 - 35% | Nil | Nil | Nil | Yes | Dangerous materials, mav ignite in temperatures above those recommended. Must be stored separately in a ventilated area as materials give off acidic vapours. No display, minimum illumination for the purpose of reproduction. CONTACT NATIONAL FILM & SOUND ARCHIVE. |
| Cellulose acetate and cellulose nitrate objects | <20°C | < 40% | 50 | 30 | 3 months | Yes | Must be stored separately in a ventilated area as materials give off acidic vapours. Soluble in most solvents. |
| Charcoal (on a substrate) | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | ||
| Clay | 10- 30°C | < 40% | 300 | 200 | unrestricted | May disintegrate in water. May contain carbonates which are soluble in weak acids. Repair materials (adhesives, fillers, paint etc) may require lower light levels and restricted display periods. | |
| Coal | 20 ± 2°C | 50 ± 10% | 300 | unrestricted | unrestricted | ||
| Composition (Compo; as used on frame mouldings) | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Embrittles and cracks with age. | |
| Copper (brass & bronze) | 20 ± 2°C | < 35% | 300 | unrestricted | unrestricted | Prone to attack from atmospheric pollutants (hydrogen sulphide, sulphur dioxide & sulphuric acid) >15% RH. Protective coating system may require lower light levels and restricted display periods. | |
| Coral | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Soluble in weak acids and prone to attack by organic acid vapours. Dyed colours are very prone to fading | |
| Cork | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | ||
| Crayon (on a substrate) | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | |
| Crystal | 20 ± 2°C | 50 ± 10% | 300 | unrestricted | unrestricted | ||
| Earthenware | 20 ± 2°C | 50 ± 10% | 300 | 200 | unrestricted | May contain carbonates which are soluble in weak acids. Repair materials (adhesives, fillers, paint etc) may require lower light levels and restricted display periods. | |
| Enamel | 20 ± 2°C | 50 ± 10% | 300 | 200 | 9 months | High-temperature sensitive: glass and metal expand differently, if heated damage may occur. | |
| Feathers | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | Must be careful not to detach combs from each other when handling. |
| Fibreglass | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | May discolour and embrittle with age. | |
| Flax | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | |
| Fur | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | |
| Gesso | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | May be soluble in weak acids and prone to attack by organic acid vapours. May weaken in high RH. Embrittles and cracks with age. May delaminate from substrate. | |
| Glass | 20 ± 2°C | 50 ± 10% | 300 | unrestricted | unrestricted | Low-silica and high-alkali glasses deteriorate in high RH. Repair materials (adhesives, fillers, paint etc) may require lower light levels and restricted display periods. | |
| Glue (animal) | 20 ± 2°C | 50 ± 5% | 200 | 80 | 6 months | Yes | |
| Gold (include leaf & gilt) | 20 ± 2°C | < 35% | 300 | 200 | unrestricted | Soft metal, prone to physical damage. | |
| Gouache | 20 ± 2°C | 50 ± 5% | 50 | 30 | 3 months | Yes | Hydrogen sulfide (from atmospheric pollution) causes darkening of lead white. Very susceptible to water damage - colour and surface changes. |
| Hair | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | |
| Horn | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Yes | Hygroscopic - will crack, warp etc in fluctuating RH. Thermoplastic - can be reshaped under application of heat and pressure. |
| Horsehair | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | |
| Ink | 20± 2°C | 50 ± 10% | 50 | 30 | 3 months | ||
| Iron (alloys) | 2Q± 2°C | < 35% | 300 | unrestricted | unrestricted | Protective coating system may require lower light levels and restricted display periods. | |
| Ivory | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Yes | Hygroscopic - will crack, warp etc in fluctuating RH. Prone to staining. |
| Lacquer (Oriental) | 20 ± 2°C | 50 ± 5% | 50 | 30 | 3 months | Substrate can be hygroscopic - will crack, warp etc in fluctuating RH. | |
| Lead | 20 ± 2°C | < 35% | 300 | unrestricted | unrestricted | Prone to attack from organic acid vapours. Wax coating provides protection from acid attack. | |
| Leather | 20 ± 2°C | 50 ± 10% | 50 (dyed) 200 (undyed) | 30 (dyed) 80 (undyed) | 3 months 6 months | Yes | Oil dressed can sweat if it gets too warm. Vegetable tanned leather is prone to red rot. Hardens with age. |
| Linoleum | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | ||
| Marble | 20 ± 2°C | 50 ± 10% | 300 | unrestricted | unrestricted | Soluble in weak acids and prone to attack by organic acid vapours. | |
| Magnetic tape (audio and video) | 5 ± 4°C | 20 ± 10% | 50 (display) Nil in storage | 30 (display) Nil in storage | use copies only, no use of master permitted | Acclimatise tape prior to playback. For tapes in frequent use, the recommended storage conditions are 1 5 ± 2°C and a maximum of 40 % RH. | |
| Masonite | 20 ± 2°C | 50 ± 10% | 300 | 200 | 9 months | May give off formaldehyde which can attack other materials. | |
| Metals (not specified elsewhere) | 20 ± 2°C | < 35% | 300 | unrestricted | unrestricted | Protective coating system may require lower light levels and restricted display periods. May be stored with vapour-phase corrosion inhibitors. | |
| Micro forms (fiche and films) | <20 °C | 50 ± 10% | 50 | 30 | use copies only, no use of master permitted | ||
| Mica | 20 ± 2°C | 50 ± 10% | 300 | 200 | unrestricted | ||
| Mother-of-pearl | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Soluble in weak acids and prone to attack by organic acid vapours. | |
| Nylon (Polyamide) | 20 ± 2°C | 50 ± 10% | 50 (display) Nil in storage | 30 (display) Nil in storage | 3 months | Exposure to light can cause discolouration | |
| Oak | 20 ± 2°C | 50 ± 5% | 200 | 80 | 6 months | Yes | Hygroscopic - will crack, warp etc in fluctuating RH. May give off organic acid vapours which can attack other materials. |
| Oil paint | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Embrittles with age. | |
| Paint | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Embrittles with age. | |
| Paper and works on paper | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | Tends to discolour and embrittle with age. Will cockle (ripple and distort) in high RH. |
| Papier-mache | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | |
| Pastel | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Do not touch surface as pastels are generally friable (powdery). Binder will become more fragile with age. | |
| Pearl | 20 ± 2°C | 50 ± 10% | 300 | 200 | 6 months | Yes | Long term storage can lead to loss of lustre. Soluble in weak acids and prone to attack by organic acid vapours. Dulled by salt water. |
| Photographs | <20°C | 50 ± 10% | 50 | 30 | 3 months | Yes | Will fade and discolour with age. Very cold and dry storage preferred. |
| Plaster | 20± 2°C | 50 ± 10% | 300 | 200 | unrestricted | Soluble in weak acids and prone to attack by organic acid vapours. May weaken in high RH. | |
| Plastic (not specified elsewhere) | 20 ± 2°C | 50 ± 10% | 50 (display), Nil in storage | 30 (display) Nil in storage | 3 months | Exposure to light can cause discolouration. Plasticisers can migrate to the surface and contaminate other materials. | |
| Plywood | 20 ± 2°C | 50 ± 5% | 200 | 80 | 6 months | Yes | Hygroscopic - will crack, warp etc in fluctuating RH. May give off formaldehyde which can attack other materials. |
| Polyethylene and polypropylene | 20 ± 2°C | 50 ± 10% | 50 (display) Nil in storage | 30 (display) Nil in storage | 3 months | Prolonged exposure to light causes discolouration and embrittlement. Water resistant. | |
| Polystyrene | 20 ± 2°C | 50 ± 10% | 50 (display) Nil in storage | 30 (display) Nil in storage | 3 months | Prolonged exposure to light causes discolouration and embrittlement. Soluble in many solvents: liquids and vapours. | |
| Polyvinyl Chloride (PVC) | 20 ± 2°C | 50 ± 10% | 50 (display) Nil in storage | 30 (display) Nil in storage | 3 months | Store separately in a well ventilated area as PVC may give off hydrogen chloride which can attack other materials and catalyse further deterioration. | |
| Porcelain | 20 ± 2°C | 20 - 60% | 300 | 200 | unrestricted | Repair materials (adhesives, fillers, paint etc) may require lower light levels and restricted display periods | |
| Rope | Yes | Rope may be constructed from many different fibres (organic and synthetic) and should be assessed on a case by case basis. | |||||
| Rubber (incl. Vulcanite and Ebonite) | 20 ± 2°C | 50 ± 10% | 50 (display) Nil in storage | 30 (display) Nil in storage | 3 months | Store separately in a ventilated area as oxidised material gives off acidic vapours. Contact with metals (especially copper) accelerates oxidation. | |
| Rubber (soft) | 20 ± 2°C | 50 ± 10% | 50 (display) Nil in storage | 30 (display) Nil in storage | 3 months | Loses flexibility and embrittles with age. Prone to attack by ozone. Oxygen-free or low oxygen storage recommended. | |
| Seaweed | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | |
| Seeds | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Yes | |
| Shell | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Soluble in weak acids and may be affected by organic acid vapours. | |
| Shellac | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Prolonged light exposure causes darkening. Tends to be brittle and damages easily. Distorts in temperatures > 30 °C. | |
| Silver | 20 ± 2°C | < 35% | 300 | unrestricted | unrestricted | Hydrogen sulphide (from atmospheric pollution) causes tarnish > 15 % RH. Protective coating system may require lower light levels and restricted display periods. | |
| Spermaceti | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | ||
| Steel | 20 ± 2°C | < 35% | 300 | unrestricted | unrestricted | Protective coating system may require lower light levels and restricted display periods. | |
| Stone | 20 ± 2°C | 50 ± 10% | 300 | unrestricted | unrestricted | Some sandstone is alkaline and hence prone to organic acid attack. Repair materials (adhesives, fillers, paint etc) may require lower light levels and restricted display periods. | |
| Stoneware | 20 ± 2°C | 20 - 60% | 300 | unrestricted | unrestricted | May contain carbonates which are soluble in weak acids. Repair materials (adhesives, fillers, paint etc) may require lower light levels and restricted display periods. | |
| Terracotta | 20 ± 2°C | 50 ± 5% | 300 | unrestricted | unrestricted | May contain carbonates which are soluble in weak acids. Original material may contain chlorides. | |
| Textiles | 20 ± 2°C | 50 ± 5% | 50 | 30 | 3 months | Yes | Dust and dirt will cause abrasion to fibres. |
| Tin/Tinplate | 20 ± 2°C | < 35% | 300 | unrestricted | unrestricted | ||
| Tinsel | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | ||
| Tortoiseshell | 20 ± 2°C | 50 ± 10% | 200 | 80 | 6 months | Yes | Hygroscopic - will crack, warp etc in fluctuating RH. |
| Water colour | 20 ± 2°C | 50 ± 5% | 50 | 30 | 3 months | Binder will deteriorate with age and become friable. | |
| Wax | 20 ± 2°C | 50 ± 5% | 200 | 80 | 6 months | Yes | Thermoplastic - may distort in temperatures above those recommended. Tends to embrittle with age. Soluble in many organic solvents. |
| Wicker | 20 ± 2°C | 50 ± 5% | 200 | 80 | 6 months | Yes | Tends to embrittle with age. |
| Wood (not specified elsewhere) | 20 ± 2°C | 50 ± 5% | 200 | 80 | 6 months | Yes | Hygroscopic - will crack, warp etc in fluctuating RH. |
| Wool (felt) | 20 ± 2°C | 50 ± 10% | 50 | 30 | 3 months | Yes | May give off organic acid vapours which can attack other materials (especially silver). |