Documents Restoration Process

We always hear or read about the restoration of a building, the renovation of old books, the restoration of an archaeological site or of a painting.  What is the meaning of restoration, documents restoration in particular?
A document that needs to be renovated is a corrupted or damaged document because of natural factors.  The document, made of paper, is affected by natural factors including heat and humidity, and chemical factors such as the acid in the paper itself. Some documents are subject to biological factors such as insects, which cause damage to many documents if they have not been discovered earlier.  In addition, accidents such as fires, floods, poor documents storage and lack of conservation can damage the document at an alarming speed.
Restoring documents is the processing of documents with the aim of bringing them as similar as their original condition to benefit from them when prolonging their life and protecting them from factors of damage.  The processes of "conservation and restoration" are linked because the restoration will save the document.  Therefore, what would be the point of restoring a document if it is kept under the same storage conditions that caused damage to it?
Certain specialized devices are used if the document is very fragile and can be damaged when touched by hand.  Otherwise, manual restoration is the usual method for the maintenance and restoration of documents.  It could be a long and complicated process, requiring several stages and involving several specialists.  Firstly, the document goes through a chemical purification process to get rid of chemicals such as acids and of dust and insects.  Secondly, the document is processed based on its current condition and the intended storage condition. Many documents are then covered with a special type of plastic to save them permanently in that condition.
Restoration is a highly specialized field; it requires people who would like to work in this area to study for a long time to gain the most important theoretical knowledge before starting any practical application. In addition, years of practical work are required to master the restoration techniques where patience, professionalism and artistic creativity are essential.