A key decisions that we had to make when preparing for our Hidden Lives exhibition was whether we should display some of the original photographs from our collection. Those of you who have visited the exhibition will know that in the end we decided against doing this and have in fact used copies of the images.
One of the reasons for this decision was our concern that displaying the photos for a prolonged period of time could lead to deterioration in their condition, mainly due to them being exposed to excess levels of light. With this in mind I thought that it might be useful to share some thoughts with you on key conservation issues related to historic photographs.
Photographs are amongst the most unstable of object types found in historic houses and can be affected by environmental conditions, poor storage and incorrect handling. In addition, as well as factors specific to photographs, general issues related to paper and framed images need to be considered.
Light is perhaps the key environmental factor to consider for photographs. They are highly light sensitive objects and should be kept in dark conditions where possible. Exposure to excess levels of light will lead to a fading or yellowing of the image such as shown in the photograph below of Costanza and William Hulton.
Relative Humidity (RH) is another key environmental factor that affects the care of photographs. They should ideally be kept in an environment where the RH is between 30% and 50%, a range that is slightly lower than that generally used for a mixed collection of historic objects.
An RH of above 60% will create conditions where mould and insects are more likely to attack photographs and a high RH may also result in the occurrence of ‘foxing’, especially on photographs mounted on card. Foxing is a conservation term for the red or brown spots that can often occur on historic paper documents and books and is thought to result from either a fungal growth on the paper or from the oxidation of iron or copper in the pulp from which the paper was originally made. An example of foxing is shown in the photograph of the 7th Lord Berwick below.
Fluctuations in RH levels may lead to the occurrence of ‘cockling’ in photographs. This is the ripple pattern often seen in paper documents which is caused by the paper expanding and contracting as the RH level fluctuates. The photograph below of the 8th Lord Berwick shows the effects of cockling.
Low temperature levels are important for photographs as these can extend the life of an image more effectively than lowering RH levels. Photographs should therefore be kept away from local heat sources such as table lamps, radiators and of course direct sunlight.
Handling of photographs should be kept to a minimum and polyethylene gloves should always be worn. Photographs should only ever be handled at their edges. A padded work board is another useful tool when handling loose photographs and foam wedge supports should always be used when looking at photograph albums, as shown in the photo below.
Without the use of these supports damage to the spine of an album is likely to occur, such as that shown in the photograph below.
Photographs need to be treated with care to prolong their lifespan and I hope that you have found my discussion of these key issues interesting and that they may be of some use to you in the care of your own photographic collections.