Mar. 2001
President's
Message
Portrait of Lynn Troy Maniscalco
Photo FAQs
Photo FAQs
Eric Kissa
Below are some of the questions
asked at the "Experts" session, answered now in more detail.
Q.:How to store slides? Can slides be stored in an unheated room?
A.:The
longevity of color slides is affected by chemical reactions and a biological
attack, mainly by fungus. Both processes are accelerated by heat and humidity.
The low temperature of an unheated room is actually favorable for storage
but high humidity is very detrimental. A better location for slides is
an air-conditioned room where the temperature is about 70-75ºF during
most of the year and the humidity is not higher than 50%. In a damp room
slides should be stored in a closed container containing a drying agent,
available in hardware stores or from Porter's, 1-800-553-2001. A common
drying agent is anhydrous silica gel which can be regenerated by heating
in an oven at 400?F for about 30 minutes to drive out water.
Before slides are stored, they
should be mercilessly sorted. Slides, which do not belong in the wastebasket,
can be stored either in transparent slide pages or in slide storage boxes.
For archival storage the storage material should be free of acids and
vapors of solvents and plasticizers.
Polypropylene pages are clear
and hold 20 slides each. A one inch high stack holds up to 360 slides.
The thicker pages are easier to handle than the thinner ones but are more
expensive and need more storage space. Polyvinyl chloride (PVC) pages
should not be used because they contain a plasticizer harmful to the slides.
Slide pages can be stored in
hanging files or ring binders. Hanging files need less space per page
and keep the page flat but slide pages in ring binders stay in the order
of filing and are easier to view. A ring binder holds about 35 to 60 pages,
up to 1200 slides. Binders equipped with D rings reduce page curl and
hold more pages than those with O rings.
Slides mounted in glass (GEPE
or Wess mounts) are too thick for slide pages and are usually stored in
slide boxes. Slides can be filed (a) in individual slots to allow air
circulation around the slide, or (b) in group sections to save space.Slides
stored as groups can be readily projected with the help of a stack loader.
Various slide storage boxes are available from Archival Image (1-800-688-2485),
Light Impressions (1-800-828-6216), and other suppliers. A Logan slide
box can hold 690 cardboard or 330 glass mounted slides.
The storage stability of slides
depends on the film and processing conditions. Kodachrome film, unlike
other color films, does not contain dye couplers and is developed by a
unique (K-14) process. Because processed Kodachrome film does not contain
residual dye couplers, the dark storage stability of slides (resistance
to fading and color shifting) is outstanding. Unfortunately, Kodachrome
KM (ISO 25) has been discontinued but Kodachrome KR (ISO 64) is still
available.
Finally, storage space can be saved and permanence problems avoided by archiving slides on CD-ROM. Optimists claim a longevity of 100 years, pessimists wonder how long equipment for reading the disks will be available.
Q.:What
is acutance?
A.:Acutance is the edge sharpness of an image on film, an important characteristic of the film. A sharp knife edge may appear as a sharp line or a diffuse line on film, depending on the acutance of the film. Acutance is not necessarily related to the granularity of the film. Some films with larger granularity generate a sharper edge than some films with smaller granularity.
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Send questions concerning photographic
equipment (cameras, lenses, accessories, filters), photographic techniques
(other than digital), and film, as well as information on international
photographic exhibitions, to: ekissa @aol.com.