For ages, we’ve been taught that we should do all we can to keep our galleries and stores close to 50% relative humidity to save our collections from a terrible fate. Well, scrub that.
Over the past 15 years or so, scientists have researched what collections actually need. They’ve found that the vast majority of things are fine in a fairly wide range of relative humidity. This squares with people’s experience that their collections are surprisingly well preserved after decades, even centuries, in buildings with supposedly poor conditions.
This evidence is challenging the view that museums should tightly control their internal environment. In the past couple of years this has been a common area of discussion among the international jet-set of elite conservators, who fly the world to attend conferences and specialist meetings.
Thanks to the efforts of Britain’s National Museum Directors’ Conference – and Tate in particular – it’s also been regularly on the agenda at meetings of the shady Bizot Group, which is a clubbish gathering of the most powerful directors of the world’s grandest art museums.
I’ve dipped in and out of some of these discussions (although sadly largely without the foreign travel), but never really understood how things should change. Now, all is clear, thanks to a conference at the end of last year, organised by the University Museums Group.
Delegates heard that the main thing to worry about is an object’s moisture content. And the best way to control that is indeed to pay some attention to relative humidity. However, changes in relative humidity have a pretty small effect on moisture in objects, especially if they are in showcases, glazed frames or cupboards.
There’s a growing international consensus that almost all things in museum collections, even most panel paintings and textiles, are absolutely fine at 40-60% relative humidity.
Some leading museums are setting themselves a wider range of perhaps 35-65%. (Quite different rules apply for some things such as certain natural-history specimens and leather; these are best kept in microclimates such as well-buffered cases or storage boxes.)
We’ve also spent decades battling to control temperature. It turns out that’s been largely a waste of time, because as far as collections are concerned it’s best to let temperature fluctuate as a way of controlling relative humidity. For visitor and staff comfort it’s sensible to aim for 16-28 degrees C in public areas (stores can go cooler with no problems for collections).
And the good news is that UK museums can achieve these conditions without air conditioning, which is good for the planet, too.
For more, see www.umg.org.uk.
Maurice Davies is the head of policy and communication at the Museums Association
Over the past 15 years or so, scientists have researched what collections actually need. They’ve found that the vast majority of things are fine in a fairly wide range of relative humidity. This squares with people’s experience that their collections are surprisingly well preserved after decades, even centuries, in buildings with supposedly poor conditions.
This evidence is challenging the view that museums should tightly control their internal environment. In the past couple of years this has been a common area of discussion among the international jet-set of elite conservators, who fly the world to attend conferences and specialist meetings.
Thanks to the efforts of Britain’s National Museum Directors’ Conference – and Tate in particular – it’s also been regularly on the agenda at meetings of the shady Bizot Group, which is a clubbish gathering of the most powerful directors of the world’s grandest art museums.
I’ve dipped in and out of some of these discussions (although sadly largely without the foreign travel), but never really understood how things should change. Now, all is clear, thanks to a conference at the end of last year, organised by the University Museums Group.
Delegates heard that the main thing to worry about is an object’s moisture content. And the best way to control that is indeed to pay some attention to relative humidity. However, changes in relative humidity have a pretty small effect on moisture in objects, especially if they are in showcases, glazed frames or cupboards.
There’s a growing international consensus that almost all things in museum collections, even most panel paintings and textiles, are absolutely fine at 40-60% relative humidity.
Some leading museums are setting themselves a wider range of perhaps 35-65%. (Quite different rules apply for some things such as certain natural-history specimens and leather; these are best kept in microclimates such as well-buffered cases or storage boxes.)
We’ve also spent decades battling to control temperature. It turns out that’s been largely a waste of time, because as far as collections are concerned it’s best to let temperature fluctuate as a way of controlling relative humidity. For visitor and staff comfort it’s sensible to aim for 16-28 degrees C in public areas (stores can go cooler with no problems for collections).
And the good news is that UK museums can achieve these conditions without air conditioning, which is good for the planet, too.
For more, see www.umg.org.uk.
Maurice Davies is the head of policy and communication at the Museums Association
