Oil paint on paper

Marike Nassy <teyler [at] euronet__nl> writes

>As a paper conservation student at the Netherlands Institute for
>Cultural Heritage in Amsterdam I'm currently working on my final
>project: the treatment of a 19th-century oil painting on paper
>(53x71 cm, paint covers paper surface completely, brown discoloured
>paper, tears and losses at the edges, different types of 'bloom' can
>be seen on the paint layer).
>
>Although the paper is not extremely brittle the objects size makes
>it vulnerable to improper handling. A treatment option I'm therefore
>considering (after speaking to some conservators and reading
>literature) is application of a support layer of Japanese paper with
>starch paste. Apart from literature research I'm very interested in
>practical experiences from paper and paint conservators concerning
>the following points:
>
>    *   risks to the paint layer (chemically and physically) when
>        using a water-based adhesive
>
>    *   adhesion of a water-based adhesive to an oil-stained paper
>
>    *   use of BEVA or other thermoplastic adhesives for lining oil
>        paintings on paper

It would help if a more complete description of the paper support
were known (heavy, glue sized, rag content water color paper?), and
if it were known whether or not the paper had been treated with, for
instance, white lead, or hide glue, before painting.

The description of the paper as, "not extremely brittle" is
subjective. However, I'll describe how I would probably approach
this problem if it came to me.

I do not know what the "different types of 'bloom'" observed might
be; was the painting varnished?  If so, the varnish might best be
removed, to the extent possible, before continuing.

If the paper support is generally sound ("not extremely brittle"),
and if there is an inter-layer (a ground) you could probably get
away with a Japanese paper lining, with the following modifications.

Make up the starch/water suspension, but don't cook it for 2-3 days;
let it soak and before cooking carefully pour off the old water and
add fresh water up to the mark.  This will produce a paste more
viscous than one which is freshly made up.

Make up a batch of hide glue, and add approximately 50% by volume of
the starch paste to the glue, well stirred in.

Use a heavy-weight Japanese paper for the lining dampened just
enough to relax it, but not over stretch it.  Paste it off with the
glue/paste mixture and line the painting as usual, but do not tamp
it; just brush strongly.

Then put it on the drying board face-in and leave it to dry with the
drying board horizontal, not leaning against a wall, or stacked in a
vertical rack, so that evaporation will be away from the painting.

>    *   adhesion of a water-based adhesive to an oil-stained paper

Oil is hydrophobic, so it is not to be expected that a water based
adhesive would adhere to such a surface.  However, a lot of oil
paintings have been faced with a layer of Japanese paper and starch
paste....

>    *   use of BEVA or other thermoplastic adhesives for lining oil
>        paintings on paper

I have used BEVA film on one such painting.  It was entitled,
"Stained Glass Window" and was intended to be viewed by transmitted
light.  The paper support was onion skin paper (a thin sheet used
under carbon paper to make copies of correspondence, etc., when
typewriters were more common than computers).

When the painting was being put into a box for protection a
projecting staple shattered a long line up the middle.

I lined a sheet of Japanese paper with BEVA-371 film and then
adhered the paper/BEVA to the painting with heat.

Then I inpainted hairlines until I was crosseyed.

Jack C. Thompson
Thompson Conservation Laboratory
7549 N. Fenwick
Portland, OR  97217
503-735-3942  (voice/fax)

                                  ***
                  Conservation DistList Instance 12:77
                 Distributed: Wednesday, March 31, 1999
                       Message Id: cdl-12-77-006
                                  ***