Housekeeping
Good housekeeping is also essential in prevent-
ing deterioration. Work areas should be kept clean
and dust free as dust can cause scratches on the
surface of film and prints. Cover work surfaces
with newsprint, which can be replaced when it
becomes dirty. Use a soft brush or a vacuum with
the nozzle covered with gauze for dusting storage
areas. Do not use cleaning agents and solvents—
they contain harmful chemicals, and wet cleaning
such as mopping can cause fluctuations in humid-
ity levels. Obviously do not place photographs
near heat sources such as radiators and pipes.
Freshly painted or varnished surfaces can give off
harmful peroxides for up to two or three weeks
and all but the very latest photocopiers and laser
printers emit ozone and should be kept away from
photographic materials. Food and drink should
never be allowed near photographs—an accident
is destined to happen! Even nicotine from cigarette
smoke can cause staining.
Storage
Poor storage of negatives and prints is the most
common cause of deterioration. Prints, transparen-
cies, and negatives should be stored separately and
good quality archival storage materials should be
used. Paper should be impurity free and unbuf-
fered, i.e., pH neutral, (pHoton and Silversafe are
recommended brands). Some papers and cards are
described as ‘acid free’ but still contain alkalines,
which can damage photographs. Polyester is the
best material for plastic enclosures, but uncoated
polypropylene and high-density polythene are
acceptable, cheaper alternatives. Polyvinyl chloride
(PVC) should be avoided as it contains plasticizers
that can migrate to the object. For similar reasons
do not use coated, translucent, or opaque plastics.
Despite their long tradition as a photographic stor-
age medium, glassine sleeves are not suitable.
Polyester and conservation papers are available
as sheets, rolls, and ready-made sleeves and envel-
opes. Hanging files, museum card boxes, and con-
servation ring binders make good storage systems,
especially for prints, roll film, and transparencies.
Cabinets should be made from baked enamel or
anodized aluminum finish. Boxes and cabinets
made from new wood or freshly painted or varn-
ished wood should be avoided.
Ideally, prints should be stored in transparent
sleeves, with unbuffered board if extra support is
required, and then placed in folders or museum
card boxes. Plastic sleeves should not be used
where the emulsion is fragile or flaking, or there is
extensive mould damage or images have been hand
colored. Platinum prints should be stored flat in
archival boxes.
Glass negatives are most at risk from physical
damage resulting in chipping, cracking, breakages,
and scratches. The plates should be wrapped in pH
neutral conservation paper and stored in museum
board boxes vertically along their long edge, add-
ing a board separator every fifth plate to give sup-
port. Plates larger than 1210 inches are best
stored horizontally, at no more than four per box
to prevent the weight crushing the bottom plate.
The original wooden boxes for storing lantern
slides are usually fine, but do check the condition
of the box and its lining material.
Cellulose nitrate film base, invented by the East-
man Kodak Company in the 1880s was quickly
copied by others and allowed the development of
sheet, roll, and cine film. It was in turn replaced by
cellulose acetate and later, polyester supports.
Nitrate and acetate bases are both prone to serious
chemical deterioration and should be checked reg-
ularly for signs of deterioration, as this can quickly
spread to affect the entire collection.
Nitrate film stock is the most notorious. Intro-
duced in the 1880s it was in use until the 1950s
(although still manufactured abroad in 1960s). It
breaks down into harmful and dangerous ele-
ments that are very acidic and can fade silver,
soften the gelatin emulsion, and rust film cans.
Nitrate film is also combustible and gives off
highly toxic fumes, a by-product of which is oxy-
gen, making fires difficult to extinguish. In the
early days of cinema there were many fatal fires
in theatres when the nitrate cine film ignited in
the projector. The first stage of deterioration can
be seen as an amber brown staining, the film then
softens and becomes tacky, producing gas bubbles
and gives off a ‘sweet’ odor before the film finally
breaks down into combustible powder. Some
nitrate can be easily identified by the word
‘‘Nitrate’’ along the edge of the negative but this
is by no means conclusive. If nitrate film is sus-
pected, a conservator should be engaged to test a
small sample—nitrate film will sink in trichlor-
oethylene. Deteriorating nitrate film should be
handled under a fume hood or wearing a respira-
tor. Cold storage in a flameproof lab freezer in a
paper enclosure is ideal but be aware that, due to
its combustible and toxic nature, storage of ni-
trate film often invalidates insurance policies.
Nitrate film stock is best copied under supervi-
sion and either destroyed through the fire depart-
ment or local authority or stored off-site in
specialist facilities.CONSERVATION