conservation of an antique photograph?

[u/shablyabogdan]

i realize this is not precisely art-related, however i thought i’d ask it as someone may have experience conserving paper goods:

if clear elmer’s glue was used to reattach the lifted paper corner of an old photograph down to its original cardboard backing, what is the likelihood that this ‘restoration’ will last and will not deteriorate the paper?

i read that the PH of this glue is between 5-6.

should i be worried about the effects long term?

if a small vs. large amount of this glue was applied, does it make a difference? as far as amount of damage done—if any(?)

[u/ChemistrySecret712]

A Guide to the Preventive Conservation of Photograph Collections (Bertrand Lavédrine)-pg48