Quick answer: Loan agreements put numbers on care. The widely adopted Bizot green band asks for 40–60% RH at 16–25 °C with limited daily drift, and lenders of wooden instruments often write tighter 45–55% clauses. Case-level humidity buffering is how borrowed instruments actually meet those numbers in transit and on display.
When an instrument leaves its home collection for an exhibition, the romance travels on paper: a facility report, a loan agreement, a condition report and a courier plan. Somewhere in that stack is a humidity clause, and it is the line most likely to decide whether the loan happens at all. Collectors lending a fine violin for the first time are often surprised that the borrower's climate data matters more than their security system.
The numbers institutions ask for
For years the default museum specification was a strict 50% RH with tight tolerances, a standard that consumed enormous energy. The Bizot Group of major international museums, whose green protocol is published through the UK National Museum Directors' Council, now recommends a broader band for hygroscopic objects: 40–60% RH, 16–25 °C, with fluctuations held inside about 10 points of RH per 24 hours. The same guidance adds the caveat that matters for instruments: more sensitive objects require tighter control based on materials, condition and history.
Wooden instruments usually qualify as more sensitive. Thin plates, hide glue joints and centuries-old varnish put many lenders in the habit of specifying 45–55%, which is no accident: it is the same band makers and conservators converge on, the one our sweet spot pillar traces across the industry, with 49% sitting at its center.
The paperwork, decoded
| Document | What it covers | The humidity angle |
|---|---|---|
| Facility report | The borrower's building, HVAC and monitoring | Twelve months of climate logs beat any promise |
| Loan agreement | Terms, insurance, environment clause | The RH band and allowed drift, in writing |
| Condition report | Documented state before and after | Cracks and seam checks are humidity history |
| Courier and transit plan | Who travels with the object and how | Buffered crates and case microclimates in trucks and holds |
| Data logs | Proof across the whole loan | Logger in the crate and the display case, downloaded at return |
Transit and display: where cases do the compliance
Buildings hold bands; journeys break them. The working answer across the loan world is the microclimate: a well-sealed crate or display case whose interior is buffered by two-way humidity media, so the object rides through airport cargo bays and gallery HVAC hiccups inside its own stable pocket of air. It is the same physics our display case guide applies at home, executed with paperwork.
This is the environment Humidi-Cure® 49% was built around: a two-way pack that holds 49% RH within about 2 points, adding and absorbing as the outside air swings, with no liquid or gel anywhere near varnish or ivory fittings. The fill is a US-patented plant fiber, food-contact safe and compostable, and each 60 g pack works for about 3 months, with enclosure airtightness the number one variable, which sealed museum casework happens to be excellent at. For institutions, the same two-way fiber platform scales from a single violin case to a gallery of sealed vitrines.
For collectors who lend
Private lenders make loans possible, and the ones who get invited back run their homes a little like institutions: a documented 45–55% environment, cased storage between exhibitions using the routine in our vintage protection guide, and a simple monthly RH log. Institutions from Seoul to Singapore to Sydney read the same conservation literature, so a collection documented this way travels internationally with far fewer questions.
FAQ
What RH do museums actually keep instruments at?
Modern practice follows the Bizot 40–60% envelope, with many instrument lenders and conservators specifying 45–55% and limited daily drift for wooden objects.
Can a loaned instrument travel in winter?
Yes, inside a buffered, sealed crate with a data logger and sensible acclimatization time at each end. The crate's microclimate, not the cargo bay, is what the instrument experiences.
What is a facility report?
The borrower's standardized disclosure of building, environment, security and handling. Lenders read its climate section first.
Do sealed display cases need their own humidity control?
Yes. A sealed case with no buffer drifts with the gallery; a sealed case with two-way media becomes the most stable environment in the building.
Case-level control, collection-level peace: Humidi-Cure® 49% Humidity Pack, 4-pack of 60 g packs, $8.99, from the instrument humidity collection.
Museums, galleries and conservators: talk to us about vitrine and transit programs via the wholesale page or info@atmosiscience.com.
Preparing a loan?
Tell us the object, the route and the borrower's spec, and we will suggest a buffering setup that satisfies the clause.
