Oil seepage to surface of white oil paintApproveRejectUn-ApproveSubscribeUn-Unsubscribe
Question asked 2018-11-19 19:27:52 ...
Most recent comment 2018-12-08 13:39:54
I am finding that after a period of about 1 year or more, surfaces where I have applied very thick areas of white oil paint have brown oil spots, as if the oil in the paint is seeping to the top. This may be due to the low quality of paint I’m using: Winton - or perhaps the kind of white: Titanium. In these cases I have not mixed any mediums into the paint. What is the cause, and can it be repaired? Can I simply paint over the surface with a higher quality white, and will that last?
Answers and Comments
I cannot say that I have experienced the exact phenomenon
that you describe. I have tried to always use higher quality oil paints for
anything other than the most trivial color assignments. W & N does freely
admit that Winton is their student line but even so, this should not be
happening. I generally think of lower grades of paints having greater
proportions of fillers and stabilizers that, I would think, could make the pigments
less likely to sink and have a surface skin of oil, which would yellow. This
could be more than offset by the lower pigmentation inherent in student grades
but still this seems surprising, I wonder how you applied the thicker strokes
of paint; by brush or palette knife. I have always been struck by how different
the surface effects of the same paint appear when using these two different
tools. This seems to go beyond the simple smooth surface left by the knife as
opposed to the textured artifact of the brush but this is a bit too esoteric
for the present discussion.
Anyway, I am sorry that I cannot give you answers that are
more helpful. Hopefully, some of our other moderators can answer with more
coherent and cogent remarks.
Finally, I would say that you should certainly paint over
the offending passages with a better quality white, preferably with a highly
pigmented, artist grade titanium white. This would likely mean that you would
apply a more pigment rich paint over a fatter paint but it is appropriate in
this case given the unsightly surface. If it were me, I would lightly abrade
the surface of the offending paint with some very fine sandpaper (given that
this is titanium white and not lead white or a mixture of titanium and another
toxic pigments, ignore this suggestion if this is not the case). 320 or 400 grit
should work. This will promote adhesion, which otherwise could have been
compromised due to the slick surface skin of yellowed oil.
I cannot speak to that, but have sent this question to Dr. Boon to see if he has any comment.
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