Does any one have more information regarding a process called "hashcharah" which is used in the process of repairing old sifrei Torah. It is some sort of chemical process that turns brown and faded ink black. Outside of Stam, it's used mainly for archives and record keeping companies make old documents with faded writing legible. It darkens the writing. I recently met a few chevrah in Benai Brak who offer this service with pretty good results - for a much cheaper price than manual repair would cost.
Therefore I am wondering...
1) Is this process ethical to use on Stam (does it last, is it the same quality as manual restoration by a sofer?)
2) What are the kashrus ramifications? (lishmah, kedushas hashem etc).
3) Are there any teshuvos, letters from rabannim about this process?
Apparently it darkens the klaf, but so do fixatives and other materials commonly used by standard restorers.
Does anyone have any further info or have experience in this process? Thanks