Abstract

It is almost certain that leather was first made as a result of rubbing oils and greases into skins as an attempt to produce a suitable material for clothing. Skins simply hung or stretched out to dry produce a hard material which, if allowed to get wet, will putrefy and disintegrate. Tanning is the process whereby a chemical reaction between the skin protein (collagen) and a tanning agent (in this case certain types of oils) results in a physical change to produce a material that does not putrefy when wetted. i.e. the skin is converted to leather.

Professor Procter in his ‘Principles of Leather Manufacture’ (1922, Chap. 26)1 sums up much of the information produced by other researchers on the subject of oil tannage by saying, ‘In its simplest form it [oil tannage] consists merely in oiling or greasing the wet skin and kneading and stretching it as it slowly loses moisture and absorbs fat. Under these conditions the fibres become coated with a greasy layer, which prevents their adherence after they are once separated by mechanical treatment. At the same time some chemical change takes place in the fibre itself, which has a part in its conversion to leather varying in importance according to the method and fat employed’. It is perhaps two to three hundred thousand years since oil tannage was discovered, its slow evolution using the most suitable kinds of greasy material. At some stage the use of smoke was found to further improve the leather, both softening and making the leather more water resistant.