some reason oiling out is under emphasized or has been
forgotten by many art instructors. Yet it is critical in
creating conservation works of art.
Oiling out is the process of applying
and rubbing in a thin coat of drying oil (linseed oil) or
painting medium to an oil painting. This is done after the
surface of the oil painting is sufficiently dry that the oil
or medium can be applied without disturbing it. Excess oil
can be wiped off afterwards. This saturates the color,
restores the sunken areas of the painting and helps isolate
the color layer from the final protective varnish.
Oil paintings should always be oiled
out when completed and are waiting for sufficient drying
before a final protective varnish is applied.
The painting may require more than one
oiling out depending on how much the painting has sunk.
Oiling out should continue until there are no sunken areas
after the painting has dried for several days. Oiling out
can also be done between painting sessions to restore sunken
areas. However, the painting should always be oiled out
when completed and prior to varnishing.
Oil paintings may appear to sink or
become dull in areas as they dry because:
- Oil is absorbed out of the upper
paint layers into the lower layers or the ground on the
painting support. This leaves the upper surface short
of oil and microscopic rough. Generally this occurs
when the lower layers are more oil absorbent than the
- The oil surface can also become
microscopic rough as a result of vaporization of the
volatiles in the panting medium leaving pinholes to the
The color appears dull as a result of
the difference in light reflection from the rough surface.
Oiling out restores the unified reflection surface to the
painting. In addition it seals any upper surface pin holes
thus when a finial protective varnish is applied it will not
contact the color layer allowing it to be removed when
necessary for conservation or cleaning.
Even if the painting is not varnished
it should be oiled out. This will unify the upper layer and
seal the lower color layer from environmental contaminates.
The rough surface in the sunken areas will also attract dirt
if the painting is not oiled out.
Two quick comments on varnishing:
- Old resin varnishes like Damar
should not be used.
- Paintings should never be
varnished until the oil is sufficiently dry. Premature
varnishing can result with the varnish reacting with the
paint film forming a tacky surface that does not dry
properly if it ever dries.