Retail commercial products have proprietary components, which are keep secret, for legitimate reasons. Since conservators want to know exactly what they are using, they prefer materials, such as Lascaux 360, which are really made for industrial applications and do not need as many things added to them as a product designed for the general public would. Some tapes are made for
library use, with circulating collections, which
must be handled extensively to be useful. To erform properly, that tape must hold the paper strongly, during that handling, while the sort of
mending that Rebecca mentioned might not stand up
to handling by the public.
Hugh
Hugh