Ideally storage should have...
-climate control
-monitors for RH, temperature, fire and theft
-each item accessioned with finding aid for accessibility.
Planning considerations will include...
-nature of the collection
-spatial requirements calculated from finding aids
-how the collection is to be used
Ideally storage
should be in a...
- central space
- away from outside walls
- heating units
- plants
- water mains
- daylight
General Guidelines
* The ideal temperature
for most products is 68°F +/- 2°F
* The ideal relative humidity level for most products is 50% +/- 5%
* Long-term storage should remain between 50°F - 55°F
* Damage to organic
material begins to occur at 45% RH or less.
* Mold will flourish at 70% RH.
Climate must remain
constant, large fluctuations are most damaging.
* "buffered"
- smooth white crisp paper, pH is alkaline or greater than 7
* "unbuffered" - soft fibrous paper, pH is neutral = 7
Areas in red
indicate the highest priority for reducing potential deterioration to that
format.
Areas in green
indicate dangerous conditions to avoid.
(SO-sids)are soft bodied insects, less than 4 mm (3/16 inch) long with long, slender antennae and chewing mouthparts. They may have four wings or be wingless. They are generally gray or brown in color. Psocids are readily identified (under magnification) by the presence of a large, conspicuous clypeus (nose). xxxxviii
| Format
|
Temp. |
RH. |
UV |
Biological
Threats |
Enclosure
|
Long
-Term Storage |
Exhibition
/ Loan |
B&W
Photos
|
Below
24° is ideal. |
30% is ideal - Never to exceed 50% |
Well-processed
silver-gelatin images are stable to light. -Resin coated papers are susceptible to light damage. Not to exceed 75 micro-lumens |
Corrosive pollutants in atmosphere and moisture. | Acid-
free; lignin-free window mat enclosure with Mylar –D or cellulose
triacetate sleeves. Buffered tissue Framed photo’s should have acid-free object boxes built of rag board, or acid-free cardboard |
Dry cool dark storage. | Levels higher than 50% RH are not acceptable. Movements between storage and exhibition should be done gradually. Handle with cotton gloves. |
| Color
Photos Unstable in both light and dark storage. |
-Cold storage vault -Below freezing point |
25% is ideal Fluctuations of no more than 5% |
Prolonged
exposure to light should be avoided. - Light intensity should not exceed 50 lux. |
Organic emulsion and dye components will attract silverfish and firebrats. | Should
be stored in chemically inert plastic sleeves made of either cellulose triacetate
or polyester (Mylar-D), un-buffered paper envelopes, and handled as little
as possible. No buffered papers. |
Humidity controlled cold storage. Each 10° reduction in temperature will double the life of color material. Signs of chromogenic dye loss or staining should be met with migration to preservation photocopy and restricted use of original. | Temperature and electromagnetic –radiation are catalysts for deterioration. Color photos should not be used for exhibition or loan. If necessary for long-term display, photos should be migrated to Fuji-inax Ceramic color photographs. |
| Video
Tape Polyester base cassette tapes, no less than 1.5 mil thickness. No longer than 2 hours in length recorded at fastest speed |
60-65°F ideal | 25-45% RH - Low humidity can create static. |
No long-term exposure to ultraviolet or natural light. | Dust, abrasive pollutants in atmosphere, electrical conduit, binders and mold growth, magnetic fields. | Tapes should be stored in Inert polypropylene or polyethylene cases. | Stored
vertically in an upright position. Duplicate tape should be stored in off-site
location. Rewound once a year. No magnetic bookends. No motorized shelves |
Use should be limited to research and not for exhibit. -Color copies should be made of high use issues. Digital transference is another possibility to increase access and decrease use. |
| Paper
-Letters -Cards -Stock certificates -Currency -Sheet Music -Speeches -architectural drawings |
60-65°F (Lower the temperature the better) |
35-60% RH | Limit exposure to UV and natural light | Silverfish,
firebrats, psocids, |
Mylar
encapsulation Acid Free-Lignin Free, Un-buffered paper folders. |
Stored in acid-free corrugated document boxes- | Viewing areas should have UV filters in place |
| Book Manuscripts |
60-65°F (Lower the temperature the better) |
35-50% RH | Limit exposure to UV and natural light | Silverfish, firebrats, psocids, Cockroaches, rodents, book lice, book worms | Acid
free Buffered four-fold manuscript and book enclosures made from rag mat
or blotter board and secured with cotton twill tape. Glassine or buffered tissue can be used for interleaving. |
Should be stored vertically on acidic barrier such as polyethylene sheeting with ethafoam, rag board or buffered papers. Dust covers of cotton, Tyvek (E) or polyethylene sheeting should be used. | Viewing areas should have UV filters in place |
| Government Documents | 60-65°F (Lower the temperature the better) |
35-50% RH | Limit exposure to UV and natural light | Silverfish, firebrats, psocids, Cockroaches, rodents | Acid free buffered files and acid-free corrugated storage boxes 12x 15 x10 | Possible candidate for online or microfilm consortium with other repository to increase access and scope of collection | Viewing areas should have UV filters in place |
Artifacts |
Temperature should not exceed 72°F. | 40-50% RH high RH and pollutants can affect salt migration in glass and ceramics without glazing. -low RH cracking
of ivory and some plastic |
Ultra
violet and natural light exposure detrimental to silk. -Fluctuation in ambient conditions accelerate the hardening inherent to rubber. |
Corrosive gasses lead to salt migration -oxygen turns rubber hard |
Glass,
plastic, - buffered Leather, rubber, metal - unbuffered High density foam can be used to make object nests |
Oversized
artifacts should be stored on rolled folder made of polyester film and acid-free,
lignin-free tubes or in flat drawers. Loose objects should be secured. Objects should fit snugly in storage boxes. |
Each item should be assessed for display needs. When there is a mixture of media, the dominant ones to consider are leather, cellulose, and plastic. |
| Textiles / Fabrics | 55°-
68°F (12.7°-20° C) |
40-50%
RH Mold growth occurs readily on textiles |
Light
exposure will damage reactive dyes. - Silks should never be exposed to ultraviolet radiation. |
Corrosive
gasses, dirt, moths, Silverfish, firebrats, psocids, Cockroaches, rodents, mold |
Interleaf
textiles with appropriate tissue. Wrap in mylar or unbleached muslim to protect from dust and handling. Tie with cotton twill.
|
Role on 1.25", 2", or 4" diameter archival tubes made of acid-free chemical pulp, buffered to a pH of 8.4, and bonded with chemically inert adhesive. Length should be the waft dimension plus 2" Store in acid-free storage boxes made from same material as tubes. |
|
Negatives |
Below
24°C Never to exceed 32°C |
30-35% RH | Prolonged exposure to light will cause embrittlement to gelatin layer. | Corrosive
pollutants in atmosphere -moisture -rodents -mold -chemical reactivity |
Should
be separated from prints
|
Not
intended for display- Should be handled with cotton gloves. -used to make positives. |
|
Ethnographic
|
60-65°F (Lower the temperature the better) Susceptible to extremes or fluctuating temperature |
Ideal Rh 50% Fluctuations of no more than 5% -Susceptible
to extremes or fluctuating RH |
Prolonged light exposure will increase fading in light-reactive dyes, and will catalyze chemical reactions | Moths,
Silverfish, firebrats, psocids, Cockroaches, rodents, corrosive
gasses, salt migration, |
-Object
boxes made of appropriate acid-free material should be constructed feathers,
fur, leather,silk, metal, wool -unbuffered |
Cool dark
storage; continuous environmental control - Build object nests to provide adequate support for materials - Use coated metal shelving to promote air circulation when necessary |
Limited display
in UV controlled areas. - Micro climates allow better control over mixed material collections. -Movements between storage and exhibition should be done gradually. -Handle with cotton gloves |
Painting |
65°
- 70° F Susceptible to extremes or fluctuating temperature. |
40%
- 55% RH. Susceptible to extremes or fluctuating RH |
Limit exposure
to UV and natural light. storage should remain dark |
Corrosive
pollutants in atmosphere -composite objects have an increased risk of deterioration |
Acid-free
backing board screwed to the verso of the stretcher bar or frame |
Each painting should be evaluated for exhibition |