I use Edding and Pilot permanent markers so I am assuming a certain degree of permanence. The uniqueness of the paper is very important -slightly shiny and resistant otherwise the markers soak in too much. I tend to be experimental with the mediums I use - more an exploration of process and not too concerned about archival longevity (perhaps I should be). The works called 'Domestic Science' are made with fruit jellies of varying flavours encapsulated in CD cases - and since 1998 a lot of them are still preserved! Especially strawberry... Makes you wonder what's in them.