What you say makes absolute sense.

i will try to answer your query – and i hope this doesn’t become a paper on the do’s & dont’s of varnishing! this is obviously based on my own observations & experiences.

any organic, textile-based artwork (canvas, paper, wool, etc) will show deterioration of some kind over time – from dust, humidity, sunlight, etc – affected by how it is displayed or stored. conservation is only a means to minimise these factors. in terms of 2d mixed media art, its archival nature largely depends on the successful bonding and/or consolidation of the layers of media used, together with some protection from outside elements as mentioned.

the surface of an intaglio print is significantly different in structure to an oil painting in that a lot of the substrate (the paper) is still exposed – it is still porous. i used this factor to colour open areas of the paper, the oil-based ink naturally resisting the diluted, water-based media. the acrylic medium is diluted so that it bonds effectively with the more absorbent parts of the paper, not as a thick topcoat over the whole work. an acrylic formulation does not adhere to an oil-based surface for obvious reasons. you will probably know that oil-based mediums continue to ‘cure’ or oxidise over many months if not years, dependent of course on its depth and viscosity. i chose not to use a spirit/solvent based varnish because of this and because it could yellow the paper, and could be quite acidic – whereas acrylic is usually ph neutral. a wax-based medium could also work but again would darken or change the colours.

technically speaking, i obviously want to protect the surface of the paper from humidity, but i have many oil-based prints in my collection that even after nearly twenty years have not faded, flaked or crackled – they are not varnished or sealed.

however, it should also be said that many artists nevertheless use the incompatibility of different media for aesthetic effects – it’s for them to decide if their work holds up or degrades after only a few years – i’m not judging that here!

my artistic objective is to create a paper-based work that is not framed behind glass – in this regard it is no different to any mixed media collage on panel or canvas. for ultimate conservation paper-based works should be hermetically sealed in a box or frame, or stored flat in the dark between sheets of acid-free tissue paper – but a contemporary artist has to balance archival issues with the necessity for their art to be appreciated as originally conceived and intended – if this creative departure were not allowed we would not have picasso’s cubist collages!

if by chance one of my own works found itself in the tate archives i think it would be less of an issue to conserve than say a kiefer, who burns, abrades, adds glass, lead, straw to his paint surfaces, etc. i once read somewhere that they used PVA to fix one of his canvases!

btw, i am not new to printmaking.

I just wonder tho, as a painter first (and printmaker only lately) if you are using oil based inks will an acrylic based vanish not cause problems in the future? I know from bitter experience in painting that acrylics do not go over oil paint.

technical answer – would say about 2-3 weeks minimum, although most of my prints were coloured & varnished a few months after the printing. the intaglio prints were under boards for a day or so then pegged up to cure properly. any varnishing would depend on thickness & density of ink on the paper – relief/block prints being quite different to intaglio prints. i use an acrylic formulation picture varnish but dilute it to eliminate brushmarks – and very thinly applied. i’d be reluctant to use anything spirit-based as this could adversely affect the fibres of the paper – although all of this would also depend on what type of paper you are printing on.