Oil Paint Not Bonding?ApproveRejectUn-ApproveSubscribeUn-Unsubscribe
Question asked 2018-02-16 16:04:02 ...
Most recent comment 2018-02-19 18:39:00
Grounds / Priming
I have an oil painting in progress that has a quite-dry, scrubbed-on Imprimatura layer of M. Graham Rapid Dry Titanium -- an alkyd oil paint which *does* have a small percentage of Zinc in it, according to the company, and which I used as an oil-based 'ground' alternative to something like a solvent-based ground because an acrylic-primed canvas is so dang absorbant and 'draggy' -- that was then painted over with a very thin raw umber layer with a small amount of alkyd medium. It's been a month now, the raw umber appears quite dry, but a fingernail can scratch off the paint on the high points of the canvas weave. I'm wondering if this is just happening within the normal curing and bonding time between layers of oil paint, or if the Rapid Dry used as a Ground was not a good idea, or there's some other red-flag reason not to proceed with this approach? Any thoughts would be much appreciated!
Answers and Comments
I've seen something matching this description before, involving layering with oil paint and alkyd medium. In my case, a fresh application of oil paint with alkyd medium was applied over a completely dry layer of oil paint without alkyd. As you describe, the new layer was easily scratched off at first, but later, when the paint became stiffer and not so "fleshy", it was not as vulnerable.
I wonder if it might be advisable to abrade or lightly grain the first layer when layering in this combination. I recall Taubes used to recommend something like this, but his advice was based on independent studio work and not scientific experiment.
It seems to me that paint that can be easily scratched or
removed from a ground is a bad sign for future longevity although it is
possible that with time the paint will dry and be more resilient. I would guess
that the paint you used for your ground was either not absorbent enough or crated
a closed film with no mechanical tooth. Conversely, perhaps the scrubbed on oil
layer was too lean.
There is nothing inherently wrong with a good quality alkyd
binder. This has been show by decades of use and testing by coatings manufactures.
I have generally found alkyd artists paints to be looser with less pigmentation
than high quality artists’ oils (this is a very complicated subject on its own
as “stabilizers” and thickeners can be added to an oil, or alkyd, to make them
very stiff and appear to be super loaded with pigment). On the other hand, those alkyd artist paints
that I have observed created far more transparent and glossier films when
compared to an unmodified oil paint film of the same pigment. I have not
experimented with Gamblin’s alkyd paint line, which I understand was formulated
to be quite lean and a good choice for underpainting. So again, I doubt that
the problem is the result of a bad material. Alkyds are perfectly acceptable
and useful in the right situations.
Galkyd may or may not be appropriate for a specific paint
effect, but it is a reliable medium for use with oil paint. Artists, like the
public at large often have strongly held opinions on subjects that are based on
faulty assumptions, misinformation, and biases. Some these become are repeated
so often that they take on the air of concrete truth. An example is the often repeated
idea that graphite somehow migrates through paint films. This is not and never
has been true but it still comes up on forums, including this one. One of the goals of MITRA is to dispel some of
Back to the alkyd containing paint. Zinc is problematic in
large percentages in the long term (search the forum for a discussion about
zinc white) but its presence would not contribute to the defect you mention.
More to the point, I will send a message to M. Graham to see
if they would like to comment on this thread. I will also send a message to
Gamblin to see if they would like to comment on Galkys and alkyd paints.
agree that the alkyd white used on this canvas was too binder-rich to
be used as a ground. A light sanding with rough sandpaper, followed by
wiping of the dust, will open
up this layer and make it more receptive to subsequent paint layers. In
the future, consider using a true alkyd/oil Ground or an alkyd white
made for underpainting (Gamblin makes both of these – our
Oil Painting Ground and
FastMatte Titanium White. Both of these products, when applied thinly have an adequate tooth to provide mechanical adhesion to subsequent paint layers).
regards to Galkyd, being a high viscosity painting medium, it levels
brushstrokes and increases gloss. If too much is added to oil colors,
early on in the painting structure,
the leveled/glossy characteristics of the resulting paint layer may
make for a closed/slick surface for subsequent layers to adhere to.
Consider this medium “fat” in the Fat Over Lean guidelines – use
sparingly in early stages and more as you build up the
painting so the structure moves in a “matte to glossy” direction, which
will help with adhesion. If you need to paint on a glossy layer,
consider a light sanding/steel wool treatment first.
For more information on FOL, please refer to our website.
It’s also worth mentioning, we also make Galkyd Lite and Galkyd Slow
Dry – both speed drying of oil colors, but are leaner than our straight
In addition to the FOL info (linked above), please refer to our
page on Solvent-Free Painting. As Solvent-Free mediums, by nature, are all 100% fat, they should be used in moderation.
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