Agarose is a rigid gel made of seaweed and it is a homogeneous polysaccharide. Rigid gel is water in solid form at room temperature and in this example we are using seaweed that is made up of over 95% of water. The advantages of using rigid gels in paper conservation is only a recent discovery.
The proceedure is as follows:
When the gel is placed over an object that is drier than itself, water travels through from the gel to the object. It is thanks to the process of osmosis that this takes place.
Once the concentration of water is increased on the object, the water is pulled back into the gel, but this time it also drags any impurities from the object back with it into the gel. This allows us to clean an area locally without immersing the whole object in a bath.
The water is released on the object slowly. I used Agarose gel (4.5%) to surface clean an area on a watercolour. The area was affected by the adhesive underneath, which created stains on the surface of the artwork that subsequently attracted dirt. I placed gels on top of the affected area and left them for a while. The only area subjected to any moisture was purely the area that the gel pieces were place on.
The yellow discolouration faded and the dirt was removed.
A successful technique, involving minimal distruption and handling to this type of item from our collections.
by Konstantina Konstantinidou (Paper Conservator)