Tips from our Conservator - Blog, Care4Art: Do artworks need to breathe?
03 November 2016
Caring 4 Art - New frame essentials (for works of art on paper)
Posted on October 16, 2016 by Craig Horsfall
In a very literal sense, it’s only living creatures that breathe and the answer to whether artworks need to breathe is a clear ‘no’.
The analogy is useful though once you consider that breathing consists of two actions; ‘breathing in’ in order to supply oxygen to support on-going chemical reactions, and ‘breathing out’ to get rid of waste by-products.
The preservation of artworks is usually helped by slowing down any on-going chemical reactions and keeping change to a minimum. This is the opposite of ‘breathing in’ to maintain life-giving reactions. By limiting air flow, the supply of chemicals available for reaction can be slowed or cut off. Different kinds of artworks are affected by different chemicals, but these can include oxygen, water, and pollutants such as nitrogen dioxide or acetic acid. The dust and mould spores always present and moved along in air can also affect artworks.
Waste products out
Artworks can give off chemicals that they have previously absorbed or that they generate themselves, whether due to physical damage, chemical change, or previous treatment and conditions. Some of these will be relatively inert, some could cause further chemical reactions if they remain in contact with the artwork, and some could be a danger to artworks nearby and maybe even be a danger to people. It is certainly worth pointing out that many art materials (i.e. polymers such as paper and plastic) give off chemicals as they degrade that have a catalysing effect, making the very reactions that produced them then go faster [so ageing reactions speed up over time rather than slow down].
From the discussions above we can can see that while a supply of airflow in can be expected to be unhelpful, the build up of waste products that might occur without airflow out might be problematic. So what can be done?
Well firstly, there is an alternative to ‘airflow out’ for the treatment of waste products. Scavenging materials can also be used to remove waste products from around an artwork by absorbing or reacting with them. Secondly, if the risks presented by airflow in is greater than the risks presented by any build-up of waste products, then it would be a fair approach to take steps to minimise airflow overall. A thorough assessment of the artwork would be required first, and future maintenance be properly planned.
Simple frames or display cabinets go a along way to cutting airflow around an artwork and are great ways of reducing exposure to dust and fluctuating conditions. Most artworks would require that the materials inside should be acid-free or effectively sealed (e.g. by using aluminium tape to cover the inside surfaces of wood frames).
Sealed packages to be inserted into frame can be made using glazing, impermeable backboards and foil dust-seals. This will almost entirely stop airflow. In such cases it is important to include scavenging and buffering materials to manage any off-gassing into the trapped air, and to rigourously exclude unstable materials.
Gaskets added to display cabinets can effectively seal cabinets. The same considerations apply for materials included within this enclosure.
For artworks going into storage or being transported, airtight wrapping materials can prove useful.
Museums and archives continue to research oxygen-free storage and display, because without oxygen no oxidative deterioration can occur. Two approaches are available, either replacing air with an inert gas or using reactive chemicals to use up all the oxygen. Both require very effective sealing, complimented by monitoring and maintenance. The long survival of organic archeology (e.g. the ancient human sacrificial victims sometimes referred to as bog bodies) within the oxygen-free environments deep within bogs illustrates the effectiveness of anioxic storage.
A paper artwork is displayed without any kind of framing.
Subjected to fluctuating conditions, dust and airborne mould spores, foxing spots develop within a few years. [Cover picture to this article]
A recently executed oil painting that includes areas of exposed, unprimed canvas.
The areas of bare canvas would be expected to accumulate dust deposits over time, and would be more difficult to clean than the painted areas. Simple framing with glazing and a backboard would protect against dust. Off-gassing from the oil paint would lead to deposits building up on the inside of the glazing over time, but these aren’t a risk to the artwork, and can be managed by opening up the frame and cleaning the glazing (maybe once a decade). Airflow is lessened to help protect the artwork, and a long-term plan considered.
An oil painting on wood panel that has been displayed in a church for several years is going on temporary loan to a gallery for an exhibition.
Wood panels are very sensitive to changes in humidity, and the air in the gallery can be expected to be drier than those that the artwork has acclimatised to over many years.
A sealed frame or cabinet could be used to maintain more humid conditions around the artwork by cutting off airflow and by adding silica gel conditioned to the required.
Airflow is prevented and conditions carefully controlled and monitored.
A collage that includes wood-pulp newsprint and photographs is to be displayed in a bathroom.
The artwork itself includes sources of migrating acids and chemically sensitive elements.
The display environment will be very humid sometimes, presenting very high risks to the artwork.
A sealed frame could be used to cut-off air flow, with buffering silica gel added to guard against any slow ingress of moisture, and scavenging materials to absorb off-gassing from the newsprint. The framing materials are to be renewed every few years.
Airflow is prevented, conditions managed, and a long-term plan considered.
A stuffed animal has previously been treated using toxic pesticides to kill insects.
A gasket-sealed cabinet is made for the artefact to prevent pesticides contaminating the display area.
N.B. Modern treatments for insect infestations use oxygen deprivation and controlled temperatures to kill insects without leaving dangerous residues.
Airflow is prevented to protect human health.
An antique dolls’ house, previously stored in a cool but slightly damp room, is moved into a warmer, slightly drier display area.
The materials making up the dolls’ house have a relatively high internal moisture content but mould growth has been inhibited by the cool temperatures. Warmer temperatures could quickly encourage mould activity before the materials have chance to acclimatise to the drier conditions.
The artefact is displayed without enclosure. Additional airflow is provided by a fan, helping moving air to reach dead airspaces within the house’s complex structure. The physical action of moving air can sometimes inhibit mould growth by breaking any exposed delicate mould strands (mycellia).
Airflow is encouraged as a monitored treatme
Read more from this blog.
If you would like to make an appointment with our Conservation team, please contact:
T 020 7561 8196