Oil Painting Medium - Who's on first?
Gary
I've been oil painting for a few years now. I've tried various types
of thinners, glazes, and recipes to add sheen, to increase drying
time, to help paint flow, and to texturize the canvas, but I'm still
confused when it comes to the whole Fat-over-Lean theory. If were not
to apply fat over lean for archival purposes, then why do we start our
oil paintings with acrylic-based gesso? Isn't it going to crack and
peel over the next decade or so? Let's just assume for a minute that
some chemist logs on and explains why this is acceptable. I'm sure
there is a reason.... I'll undestand.
But what really confuses me is the level or degree of fat you can or
cannot apply to another level as used in some glazing techniques. If I
start a canvas with half and half (pigment/linseed oil), as in the
highest quailty oil paint straight out of a tube, then anything I mix,
be it turp, liquin, stand oil, ...the second go round, will cause it
to break down over the years and flake off. Am I right?
How do I know what recipe I can use over another? For instance, I
usually start with a general recipe of linseen, turpenoid, and a
little liquin then (when dry) glaze with a mixture of liquin, gum
turp, & stand oil. How exactly do I know (other than listening to the
guy that gave me the glazing recipe to begin with) that this medium
will hold up over time? And over my primary medium? And what if I run
out of medium half-way through my painting. Now I have to mix new
glaze stuff. What if my ratio isn't exactly like the first mix. Will
extra gum turp and less liquin cause severe trauma to the underlying
paint? Help, Anyone...
Is there an exact science out there as to what I can and can't mix
together or can and can't add to another layer? Maybe I'll take up
watercolors, but then there is gouache and water-soluble oils, what
if add,.... ah hell with it ;)
Thanks in advance,
Gary
Andrew D
cfd...@juno.com (Gary) wrote:
>Hi All,
>I've been oil painting for a few years now. I've tried various types
>of thinners, glazes, and recipes to add sheen, to increase drying
>time, to help paint flow, and to texturize the canvas, but I'm still
>confused when it comes to the whole Fat-over-Lean theory. If were not
>to apply fat over lean for archival purposes, then why do we start our
>oil paintings with acrylic-based gesso? Isn't it going to crack and
>peel over the next decade or so? Let's just assume for a minute that
>some chemist logs on and explains why this is acceptable. I'm sure
>there is a reason.... I'll undestand.
There is a positive trade off since acrylic gesso is more resistant to
changes in humdity and so while it may be "flexible" in one sense, it
doesn't expand and contract with environmental changes to the extent that
raw canvas does. For this reason, on solid supports such as timber,
masonite or mdf, its flexibility isn't even an issue and it is generally
highly recommended - though it is usually advisable to prime both sides of
the board so that it doesn't warp.
>But what really confuses me is the level or degree of fat you can or
>cannot apply to another level as used in some glazing techniques. If I
>start a canvas with half and half (pigment/linseed oil), as in the
>highest quailty oil paint straight out of a tube, then anything I mix,
>be it turp, liquin, stand oil, ...the second go round, will cause it
>to break down over the years and flake off. Am I right?......
The theory goes that turps doesn't enter into the fat over lean rule since
it thins the paint but evaporates out and as such doesn't affect the
actual ratio of oil to pigment in the *dry* paint film.
Liquin will certainly throw a question mark into the discussion since it
is alkyd based and fat over lean doesn't apply to alkyds - but as part of
a mixture with oil???? That's anyone's guess.
As for remixing a medium with slight variations in ingredient ratios, I
can't imagine it would matter. A big variance is a different story so if
you must mix your own medium, be consistent.
Alternatively, paint wet on wet and ignore fat over lean.
Andy D.
"I'm a great speller - but a hopless tpyist!"
Tina Mammoser
over acrylic gesso (which is lean as you can get - no oil). Subsequent
layers should have more oil content (ie. straight from tube or less lean
medium than the previous layer).
The reason is that a lean area will absorb oil from other layers, which
increases it's content or surface area in effect (not so much that it's
visible of course). So if you paint over an oiler layer with lean paint
it will absorb oil from *below*. This will cause the layer below to
shrink as it loses oil content. The top layer will have less hold because
the amount surface area it adhered to has changed - this causes it to
buckle in a sense, which the visible result of is cracking. Of course, it
can also flake off. That a very general explanation and I may not have
all the technical bits exactly right but hopefully it's understandable.
So, decrease the amount of medium in each new layer. That's a good
general rule.
Tina.
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Tina Mammoser
> is alkyd based and fat over lean doesn't apply to alkyds - but as part of
> a mixture with oil???? That's anyone's guess.
I've broken the fat over lean rule by finishing with a liquin layer - I had
cracking within weeks. :( :( :( It was something I did without thinking and
because I needed a quick fix on a painting.
Niall
Tina.. I was led to believe that is you
start with turpy mixes, decrease the amount by the layers
and then you get to neat paint, then you add more oil to get fatter layers
if you are layer over neat paint
I.e. the oil is the fat. Is this wrong!?
(Damn, I thought I had this sussed!)
TIA
niall
Andrew D <right@the_end.of.my_tether> wrote in message
news:right-12030...@i172-171.nv.iinet.net.au...
Paul Mesken
wrote:
>> Liquin will certainly throw a question mark into the discussion since it
>> is alkyd based and fat over lean doesn't apply to alkyds - but as part of
>> a mixture with oil???? That's anyone's guess.
>
>I've broken the fat over lean rule by finishing with a liquin layer - I had
>cracking within weeks. :( :( :( It was something I did without thinking and
>because I needed a quick fix on a painting.
>
These alkyds sure dry quickly. Amazing stuff, good for underpainting.
I used Kremer's Alkyd GG (the so called "brushable" version) purely
for testing purposes and some pigments reacted quite strange, as if
they were "pushed out" of the layer, film got very granular and rough.
OTOH it worked miracles for cobalt violet (PV 49 in this case, quite a
difficult pigment to use pure), a very fine satin look, the color a
bit darker than the pigment itself, completely leveled out.
C. Enna
>But what really confuses me is the level or degree of fat you can or
>cannot apply to another level as used in some glazing techniques.
I still find Mayer's ARTIST HANDBOOK to be
the best source of information on questions
such as this. Ever referred to it? Your
local library (in the USA) should have a
copy and hopefully it will be the latest
edition although this question can be answered
by earlier editions too.
As for myself, I've neve worried about sticking
to the rules, and the "fat over lean" rule is
one of those. I never even think about it when
painting, but then I am consistent in my
application of paint and don't vary the ingredients
throughout the course of completing a painting.
Paul Mesken
>Hi All,
>I've been oil painting for a few years now. I've tried various types
>of thinners, glazes, and recipes to add sheen, to increase drying
>time, to help paint flow, and to texturize the canvas, but I'm still
>confused when it comes to the whole Fat-over-Lean theory. If were not
>to apply fat over lean for archival purposes, then why do we start our
>oil paintings with acrylic-based gesso? Isn't it going to crack and
>peel over the next decade or so? Let's just assume for a minute that
>some chemist logs on and explains why this is acceptable. I'm sure
>there is a reason.... I'll undestand.
>
Acrylic gesso is ofcourse about as lean as one can get. Some doubts
remain however due to its flexible nature. OTOH it doesn't "flex" by
itself, if applied on a stiff support then it shouldn't be a problem
(like MDF which doesn't warp by itself although it alters its shape
due to moisture and even gravity -> completely sealing and rigid
support give the solution). I have doubts about the adhesion of oil
paints on acrylic gesso myself, especially since I get my acrylic
ground as smooth as possible. I can and have wiped off entire oil
paintings from their acrylic ground with sand paper sponges (that's
probably not what they're called in english but I guess it's clear
what I mean :-) without any trace of pigments in the acrylic gesso
thus hardly any mechanical adhesion.
However, real gesso (the glue/chalk/pigment ground) appears to me to
provide the better mechanical adhesion (the paint is sucked into it,
unlike acrylic gesso). It's not easy to make it right however, but you
can get it far whiter and smoother than acrylic gesso (with pumice
stone for instance). If it "crackles up" then it crackles up real
quickly (like in an hour) and this is an indication the mix was not
right (too much or a too strong glue). Ofcourse the real gesso should
never be used on a canvas with stretchers (it's brittle stuff).
And then there's ofcourse the lead white primer which can be applied
on a canvas with stretchers. This stuff will stand the test of time
(it only questionable if the painter who applied will stand the test
as well ;-)
>But what really confuses me is the level or degree of fat you can or
>cannot apply to another level as used in some glazing techniques.
Unless you glaze an inch thick then there shouldn't be any problem. A
glaze is always extremely thin and this decreases the chance of
crackling.
For questions of permanence you can check out "The artist's handbook
of materials and techniques" by Ralph Mayer. There's a little chapter
called "Simple rules for permanence", the "fat over lean" business is
explained and lots more. No oil painter should be without this book.
Tina Mammoser
> Tina.. I was led to believe that is you
> start with turpy mixes, decrease the amount by the layers
> and then you get to neat paint, then you add more oil to get fatter layers
> if you are layer over neat paint
Yes, that's right. Not quite what I do since I switched to acrylics last year.
;)
> I.e. the oil is the fat. Is this wrong!?
Yes. er. No. er, Yes - the oil is the fat. No, you're not wrong. :)
Andrew D
>You do seem confused. The rule is: fat over lean. So yes, you can paint
>over acrylic gesso (which is lean as you can get - no oil). Subsequent
>layers should have more oil content (ie. straight from tube or less lean
>medium than the previous layer).
But the actaul reason for painting fat over lean is so that each
subsequent layer is more "elastic" than the one underneath so that it will
expand and contract as the layer below goes through its drying process
(which causes it to expand and contract). So while acrylic gesso contains
no oil, it is more elastic than any dry oil film and so can be considered
as "fatter".
>The reason is that a lean area will absorb oil from other layers, which
>increases it's content or surface area in effect (not so much that it's
>visible of course). So if you paint over an oiler layer with lean paint
>it will absorb oil from *below*. This will cause the layer below to
>shrink as it loses oil content. The top layer will have less hold because
>the amount surface area it adhered to has changed - this causes it to
>buckle in a sense, which the visible result of is cracking. Of course, it
>can also flake off. That a very general explanation and I may not have
>all the technical bits exactly right but hopefully it's understandable.
I think it's basically wrong. More oil means slower drying in the
long-term and therefore more elasticity in the paint film. As oil paint
dries, it expands then contracts (nothing to do with the top layer
absorbing the oil). If the top layer dries "hard" before the bottom layer
has finished expanding or contracting, it will crack.
As an experiment, put a thick layer of poster paint (I know it isn't oil
paint) on an inflated balloon. Let the paint dry hard then let the air out
of the balloon and see what happens to the dry paint. Try the same thing
with an empty ballon and inflate it when the paint is dry. Most of you
will know what's going to happen without actually trying it.
In short, in oil painting, you want the bottom layers to dry before the
top layers (and drying is a process that occurs over years, not days).
Leo Papandreou
You have to modify your medium's constituent ingredients by volume in order
to obey the fat over lean rule--there is no practical way to load your brush
with more or less medium.
Whatever your medium, successive layers require progressively more oil by
volume. If your medium is a mixture of oil and turpentine, for example, then
two parts oil and one part turpentine is going to be fatter than one part oil
and two parts turpentine. The turpentine evaporates, but the oil does not,
and there will be more of it on your brush.
Fat over lean can be tricky if you vary the medium, or rather, its ingredients,
between layers. It is legal to do that but dangerous. Unless you know what you
are doing, you might create an explosion and lose an eye.
Decide instead on one set of ingredients葉ypically, an oil, a volatile thinner,
a drier and a varnish--and play with the volume of the oil. I would classify
Liquin as an oily ingredient, unless I were mixing it with an oil or a wax, in
which case I would, in successive layers, diminish the Liquin's volume relative
to the oil and/or wax. However, maybe you should take advice about Liquin from
someone who knows something about it.
Acrylic is perfectly lean擁t has no oil content at all. Despite the fact oil-
primed supports exist, some oil painters paint over acrylic grounds, perhaps
because they suffered a traumatic sexual experience when they were young. As
for acrylic paint itself, the people who use it like paint that bounces back at
them. Perhaps they suffered a traumatic sexual experience when they were young.
Dr. Slick
> > Liquin will certainly throw a question mark into the discussion since it
> > is alkyd based and fat over lean doesn't apply to alkyds - but as part of
> > a mixture with oil???? That's anyone's guess.
>
> I've broken the fat over lean rule by finishing with a liquin layer - I had
> cracking within weeks. :( :( :( It was something I did without thinking and
> because I needed a quick fix on a painting.
>
Ok, but liquin is considered lean to you? ok, it's
"oil-modified alkyd" based, but does this mean it's leaner?
I've read that one should start with turpentine as a medium,
for the underlying tints (lean), then add more linseed oil (fat) to
the medium as you go along (less turps, more oil). So does liquin
have any oil in it if it's an oil-modified alkyd?
I just read a manufacturer's recommendation that you should use
more Liquin as you go along.
I've used Liquin as a final glaze on a portrait, and no
cracking yet (many months), with a gloss damar varnish final coat.
Slick
Tina Mammoser
> "oil-modified alkyd" based, but does this mean it's leaner?
That was something I wasn't going to go into actually. I drew up a chart of percentage
of liquin and whether the result is fat or lean for various pigments - since different
pigments require different amounts of oil as binder, each tube is different. Liquin can
be fat or lean depending on how you use it. Another problem is that Winsor & Newton
won't divulge the percentage of oil that makes up Liquin, making exact calculations
difficult. Anyway...the original poster didn't seem to be looking for that detailed a
level of information. And there's still the issue of alkyd being different and not all
artists agree on the results just as not all oil artists feel comfortable using acrylic
gesso.
C. Enna
right@the_end.of.my_tether says...
>I think it's basically wrong. More oil means slower drying in the
>long-term and therefore more elasticity in the paint film.
Since we're getting 'so technical' here for
a change, may I suggest NOT using the term
'drying' when speaking of the chemical changes
an oil paint film goes through. The evaporation
of the solvents that evaporate may be defined
as 'drying' but that occurs virtually overnight.
The rest of the process is one of oxidation and
polymerization - as I understand the chemistry.
This reaction of the oils with air (and light,
as we've recently discussed) goes on over a
period of about six months, according to the
authorities on the subject. Hence on is advised
not to apply a final varnish until after six
months has passed.
C. Enna
koan...@earthling.net says...
>As for acrylic paint itself, the people who use
>it like paint that bounces back at
>them. Perhaps they suffered a traumatic
>sexual experience when they were young.
Here's a sexy little experiment for anyone wanting
to test the advantages of acrylic over oil:
Take a piece of glass - window, mirror whatever
you have at hand. Lay it flat. Apply several
layers of acrylic to a small area, and then
several layers of oil paint. Of course you'll
have far longer to wait between coats of oil
paint. Now let 'dry' until firmly set - again
the oil paint may take days to firmly set.
Now, wet the acrylic film with warm water and
peel it from the glass. What do you see? Try
wrapping it around the pinky you use for probing
orifices and see what happens. Sexy what?
Now try the same thing with the film of oil
paint - only I don't think hot water is going
to release it from the glass. You can figure
out what will work for that. And notice what
you have once the film is lifted. Then try
wrapping it around the same finger. Hmmmm?
Leo Papandreou
However, if you do not like the working and visual properties of acrylic, you
might find any number of things were sexier than spongy layers of rubber that
suck ambient muck from the air. I think if you view the matter disinterestedly,
you will find there are two types of people in the world: evil acrylic-doers--
mad scientists with foolish ideas about immortality--and freedom units roaming
the landscape in pursuit of life's simple moral pleasures and the occasional
economic opportunity.
--
Leo Papandreou
No stranger to sadness, I am learning to care for the happy.
Paul Mesken
>In article <1146a1e0.03031...@posting.google.com>,
>koan...@earthling.net says...
>
>>As for acrylic paint itself, the people who use
>>it like paint that bounces back at
>>them. Perhaps they suffered a traumatic
>>sexual experience when they were young.
>
>Here's a sexy little experiment for anyone wanting
>to test the advantages of acrylic over oil:
>
Artzy fartzy talk
NO OIL! NO ART! ;-)
C. Enna
>you will find there are two types of people in the world: evil acrylic-doers--
>mad scientists with foolish ideas about immortality--and freedom units roaming
>the landscape in pursuit of life's simple moral pleasures and the occasional
>economic opportunity.
Either I've forgotten how to count to 'three' or
you have. Let's see - evil acrylic-doers
mad scientists
freedom units (plural noted)
C. Enna
says...
>Artzy fartzy talk
>
>NO OIL! NO ART! ;-)
OIL is CLARK KENT! ACRYLIC is SUPERMEDIA!
Up up and awaaaaaay....
NightMist
wrote:
Oil is for cooking with.
Though it might be the medium of choice if you were painting a salad.
Especially if the salad were for a dinner celebrating food and art
critics. Use LOTS of flake white, cadmiums and cobalts, a dash of
true vermillion, and maybe some indian yellow genuine just for taste.
Barbara
--
everybody is somebodys chew toy
Paul Mesken
wrote:
Yummy, cow piss, I wonder if it's still available :-)
Erik A. Mattila
Actually, Jack, linseed oil doesn't completely stabilize until around
200 years, during which time pigment molecules are collected and moved
into very tiny aggregates. So a painting becomes more transparent with
time - the Rembrants we like to "stare into" like a hubble telescope
image were much flatter when fresh. I think I read that in "Rules of
Permanent Painting" British Royal Academy, an old edition ("plywood and
hardbard had just been invented, and added to end of the chapter on
painting panels..."two new products have been developed in the U.S...."
something like that.
Erik
>
>
>
>
>
Andrew D
koan...@earthling.net (Leo Papandreou) wrote:
[snip]
>Fat over lean can be tricky if you vary the medium, or rather, its ingredients,
>between layers. It is legal to do that but dangerous. Unless you know what you
>are doing, you might create an explosion and lose an eye.
So you should paint with your eyes closed? That explains Picasso.
Andrew D
>In article <right-13030...@i165-209.nv.iinet.net.au>,
>right@the_end.of.my_tether says...
>
>
>>I think it's basically wrong. More oil means slower drying in the
>>long-term and therefore more elasticity in the paint film.
>
>Since we're getting 'so technical' here for
>a change, may I suggest NOT using the term
>'drying' when speaking of the chemical changes
>an oil paint film goes through. The evaporation
>of the solvents that evaporate may be defined
>as 'drying' but that occurs virtually overnight.
Ahhh - but then we consider a set of catalysts known as "driers", which
suggest that even the oxidation process is considered as drying. ;)
C. Enna
>Actually, Jack, linseed oil doesn't completely stabilize until around
>200 years, during which time pigment molecules are collected and moved
>into very tiny aggregates.
Interesting. The kind of trivia that clogs
men's minds! In my case, in one side and
out the other!
Curious who did the 200 yr research on
the subject. Methusala, no doubt.
C. Enna
right@the_end.of.my_tether says...
>Ahhh - but then we consider a set of catalysts known as "driers", which
>suggest that even the oxidation process is considered as drying. ;)
>
>Andy D.
Precisely, and I addressed that in another
thread somewhere in this forum. I compared
the term 'setting' to 'drying' -- analogous
to the 'setting of concrete.'