Why Temperature and Humidity Belong in Every Archive

The reason we record the temperature and humidity at every archive storage location is to preserve evidence of the conditions collections actually experience. Air may feel fine during a brief visit, but an archive needs a year-by-year account of warm nights, leaks, open doors and damp shelves. Those fluctuations can damage film, photographs, magnetic tape, paper and optical media before damage becomes obvious.

Records also distinguish a one-off excursion from a persistent problem. A graph of seasonal drift tells a different story from a sudden spike, and the response is not the same. For Gauhati Cine Club, whose work in Assamese film culture gives context to its historical holdings, readings are responsible stewardship rather than box-ticking. They help protect rare moving images and related documents while keeping that history available for study and public programmes.

What a temperature and humidity record actually shows

Temperature is usually logged in degrees Celsius, while humidity is recorded as relative humidity, or RH. RH expresses the proportion of water vapour in the air relative to the maximum it can hold at that temperature, so the same percentage does not represent the same moisture level throughout the day. As air warms, its capacity to hold moisture rises. Stable temperature and RH reduce repeated expansion and contraction in stored materials.

Every location needs its own record because one building-wide figure cannot describe every shelf. A room beside an exterior wall can swing more than an inner store; high shelves may be warmer than low ones; and cabinets near windows, roofs, pipes or entrances form their own microclimates. Reviews should track daily minima and maxima, average RH and time outside the preferred range. Paired with maintenance notes, those patterns reveal weak seals, failed dehumidification or leaks.

Different media have different vulnerabilities

Film is especially sensitive. Acetate film can develop vinegar syndrome, producing acidity and irreversible shrinkage. Colour dyes can fade, and fluctuating moisture encourages corrosion or mould. Polyester-based film still benefits from controlled, stable conditions. Lower temperature and moderate RH slow chemical change, but the target depends on each format, age and condition.

Magnetic sound film, video tapes and audio cassettes have other risks. Hydrolysis can make tape sticky or brittle, and sticky tape can shed residue onto playback heads. Paper scripts, photographs, posters and publications can cockle, stick together or support fungal growth at sustained high RH. Materials with different needs should be separated in clean, inert supports and suitable cabinets.

Digital files are not automatically safe from the environment. Optical discs can warp, labels and adhesives can deteriorate, and drives may fail in dust or excessive heat. Digital preservation also needs redundant copies, checksums, durable formats and regular testing. Environmental records cannot replace backup, but they keep storage conditions stable enough for the hardware and media holding the cultural record.

Why each Assam storage location needs its own data

Assam makes location-level monitoring especially meaningful. Guwahati’s pre-monsoon heat, thunderstorms and intense seasonal humidity test storage buildings, while monsoon rain challenges roofs, walls and drainage. A break in the rains can leave damp behind shelving. Within one compound, upper rooms, ground-floor rooms and metal cabinets may behave differently. Monitoring each collection environment allows intervention before damage spreads.

Other risks are practical: water through roof joints, rising damp, sunlight through vents, insects and dust drawn in as buildings age. Air-conditioning may cool a room while leaving RH untouched; separate heating can make the air very dry. Rack-height and low-level readings, plus checks behind shelving and inside densely filled cabinets, provide a more useful map than a corridor sensor.

This documentation supports the public-facing role described by Gauhati Cine Club, where cinema is treated as both art and history. The logs are not an end in themselves. They preserve evidence of how artefacts have been kept, flag changes in conditions and guide conservation work before an emergency becomes loss.

A practical environmental monitoring routine

A workable system combines fixed and portable data loggers. Fixed units provide continuous coverage, while handheld devices check microclimates behind shelves or inside cabinets. Readings should be downloaded regularly and stored with collection records. Metadata should state each device’s location, sampling interval and checks. Batteries, clock accuracy and calibration also need attention, because a number without context is difficult to interpret years later.

Thresholds should follow the material rather than a generic checklist. Nitrate film needs strict fire and temperature controls; fragile paper may need a narrower RH band; and new material should be quarantined until assessed. Sensible procedures define safe ranges, alarm levels, response times and an escalation contact, simply enough to follow during busy festival periods. Preventive care—airflow, filtered enclosures, pest checks and keeping collections off the floor—often protects more effectively than relying only on chillers or dehumidifiers.

Lessons from Australian collections

Australian collections offer useful comparison without requiring an identical climate. The National Film and Sound Archive in Canberra shows how public access and preservation can operate together, with environmental controls protecting film and sound while selected material remains available for research and exhibition. Australian guidance for managing records, including AS 5033, likewise reinforces documented environmental management.

Conditions vary dramatically across Australia. Tasmania has cool, changeable seasons, Melbourne can swing quickly between warm and cold, northern Australia has humid summers and a pronounced wet season, and inland areas can move from very hot days to cool nights. A Canberra strategy may fail farther north without stronger dehumidification, while a northern strategy would be wasteful in Tasmania. Australian suppliers and collection managers need equipment and thresholds suited to the site and budget, whether collections sit in a purpose-built repository, museum store or clubroom.

The Australian preservation market also shows the cost of specialist work: film stock, scanning services, cold storage and repair expertise are limited and often expensive outside major cities. Preventive monitoring is comparatively economical because it reduces avoidable treatment and digitisation. Australian workplace talk is often plain about this: a system that is not up to scratch needs attention, not a reassuring shrug. That discipline suits an archive in Assam, where a preserved reel may hold a performance, location or memory that cannot be replaced.

Support this work by joining Gauhati Cine Club, attending screenings and discussions, volunteering with collection activities, or contributing towards preservation supplies and digitisation. Membership keeps film programmes and archive projects connected to the public that gives them value. People with conservation, film-handling or documentation skills can also offer practical assistance, while organisations with cold-storage capacity may explore partnerships.

Before a screening or club event, learn about the organisation’s history, archive and membership options, share accurate information about Assamese cinema, and donate responsibly kept materials with their provenance. A sustained culture of preservation begins with ordinary participation: visit, contribute, document and help keep the evidence of moving images alive.