Casein as very diluted underpainting for oil painting?ApproveRejectUn-ApproveSubscribeUn-Unsubscribe
Question asked 2018-03-15 13:20:14 ...
Most recent comment 2018-03-28 21:50:55
I now know that it's not advisable to dilute oil paints with odorless mineral spirits or other solvents for a washy underpainting, as there may be problems with binding (among other issues). Some folks advocate just painting from the tube without solvents, and scrubbing the paints around, but I enjoy the fluidity of a more liquid underpainting.
I've become interested in casein as an underpainting, and recently purchased and watched James Gurney's "Casein Painting in the Wild" video available from his wonderful blog, http://gurneyjourney.blogspot.com. I noticed that with his casein plein air paintings, he starts out with a very watered down wash of casein mixed with water and then builds up with more opaque layers of casein. I'm wondering whether this very watery casein underpainting in itself (without the layers of opaque casein), painted on an panel primed with acrylic "gesso" would have sufficient binding power (both to the acrylic gesso and to subsequent layers of oil paint).
Answers and Comments
Sorry for the late response. Richeson recommends casein as an underpainting for oils, and instructs that it can be used over acrylic dispersion painting ground (gesso). They caution against applying casein over any ground containing oil, so that would also include alkyd and traditional "oil gesso" formulas. I think the proposed thin underpainting would be a sound approach, avoiding impasto and broad, thick applications. Ampersand recommends a rigid (panel) support for casein, so I would follow that advice and avoid using stretched canvas, even with thin applications.
I am afraid that rather than having the benefits of both
mediums, mixtures like this generally end up having the deficits of both and
lack the virtues of either. Certainly very small amount of oil can be, and are,
added to casein emulsions. A representative from Richeson mentioned that they
add small amounts of oil to their Shiva Casein paints during our materials
session at CAA this February. This is probably only added as a plasticizer and
for tube stability. Casein is a very brittle binder and a tiny amount would
probably lessen this to a small extent. I would still not recommend painting
casein paints on canvas.
There are technical reasons not to add oil in substantial amounts
to casein. Casein containing large amounts of oil are known to yellow strongly.
Mayer strongly cautions against this. It is certainly true that mixing oil
paint with casein paint is not really creating an emulsion unless the two were
vigorously mixed and mulled and even then a proper emulsion is probably not
created. You would likely create a paint that had swirls of very brittle casein
between or surrounding bands of very flexible (at least initially) oil paint.
That is a perfect recipe for cracking and paint delamination. Additionally, it
is really not technically possible to create a paint that really straddles the emulsion inversion point and allows for alternating between water and organic solvents. These mixtures are physically far
more complicated than this. This subject was brought up many times by
scientists at the recent tempera conference hosted by the Dorner Institute in
Coincidentally, the mixtures that you mention actually
remind me of the “mixed technique” popularized by Max Doerner where egg
tempera/oil/resin emulsions were painted into oil glazes. These were very successful
at creating effects that were hard to accomplish by other means but unfortunately
resulted in paintings that were prone to cracking and delamination, excessive
yellowing, and solvent solubility.
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