>>The most archival methods are sepia and selenium toning. Gold is not as
>>good and platinum toning, which replaces silver for platinum, leaves a
>>significant amount of silver which, with Ilford papers anyway, is more
>>vulnerable than straight, untoned silver prints.
>>The above was verified empirically by Ilford back in the days when "we"
>>were working on a new paper with superior archival qualities -later named
>Is this true of both sulfide and thiobarbamide (thiorea) sepia processes?
This is (or was) true with the sulfide process on Ilford papers. I don't
remember if the thiocarbamide toner was used. I don't have easy access to
my correspondence of some 23 years ago.
Fredericton, New Brunswick, Canada