Using Oils with Acrylics

16 Pages·2011·0.71 MB·English

JUST PAINT
Published by Golden Artist Colors, Inc. / Issue 24
Using Oils with Acrylics
We have been debating the content
of our Just Paint Newsletter, trying to
define our direction as we move forward
By Sarah Sands
to champion the research, innovation
and value of modern coating technology, It all comes down to stresses and or, more bluntly, just too new. Even
especially the acrylic resin. Yet we are now
strains of one sort or another. Almost while admitting the shortcomings of
also a company that manufactures one of
everything about an oil painting will traditional preparations – after all,
the most beautiful oil paints in the world.
swell and contract, stiffen and flow, the vast number of oil paintings done
Should we keep our interest solely in the
in response to the environment or throughout history have come to us
writing of articles on acrylic, staying true
to our roots as a company, or can we feel physical handling. To make matters cracked and in varying states of repair
comfortable in sharing our knowledge and worse, the degree and nature of these – they will often state their preferences
interest in other traditional media? In changes will themselves change over as “better the devil you know than the
the last 30 years we’ve generated a good time as the various materials undergo devil you don’t.” By now one would
understanding of traditional materials
their own internal processes of aging. think all these issues would have been
especially as artists have pushed us in that
In the end, a stretched oil painting is completely resolved by conservation
direction, both in making custom oil paints
a battleground of competing forces, a scientists, and best practices hammered
as well as working with many of the artists
dynamic system constantly on the go. out and well documented. But no. As
that continue to combine both acrylic and
oil. We have finally come to the conclusion Toss into this arena the question of we work to dispel many of the myths
that Just Paint is just that – all paint, surrounding the use of acrylic grounds
whether oils can be safely used over an
and should contain information necessary under oils, we simultaneously lay open
acrylic ground, or even further, on top
to inform all our customers of the most new questions and avenues of inquiry
of acrylic paints and mediums, and one
important technical issues within the vast that, for the time being at least, we can
enters into a battleground of a different
field of artist paint technology. It should
only fill with our best conjectures.
also provide insights to future research as order altogether. Traditionalists

well as be inspired by the innovation and and purists will decry the use of any
The Language of Mechanical
conversation that has kept us all passionate modern materials, or else hint at dire
about sharing and supporting the most results attributed to excessively worn- Engineering
complete information resource we can out generalizations: that acrylics are Some of the most promising
provide on all our products.
too flexible, too closed, too untested research into this area has been done
To this end, this issue features our
first article on grounds for oil paintings.

We can’t think of a more requested topic
than, “what is the appropriate ground for
oil paintings?” Most artists working in oil
are currently working on top of an acrylic
ground. So as a bridge to both our worlds
of acrylic and oil, and to provide a greater
understanding of the most important bridge
for a painting, that between the support and
the paintings, Sarah Sands’ article, “Using
Oils with Acrylics” will begin to open wide
the technical issues facing artists from the
ground up. In continuing the review of
grounds, Amy McKinnon has written a
complementary article, “Make a Mark,”
sharing the insights of how many of our
products are performing as surfaces for a
wide range of drawing media.
For all our Just Paint readers, we will
continue to share our passion for making
paint and the recognition of all of us for the
trust you place in us in the continued legacy
of the works created with our materials.
Figure 1: A simplified Stress/Strain diagram with a Yield Point.
Mark Golden
Issue 24 page 1 ©2011 Golden Artist Colors, Inc.
through the lenses of mechanical
engineering and material science.
.01
These fields have probed and prodded
almost every physical aspect of a
painting, and in the process have
Swelling
provided deep insights into how a
.005
painting functions as a system and
%)
what the requirements might be for n (
ai
making artwork that has a firmer Str
footing and a more stable structure. g
ellin 0
Before exploring some of this w
S
territory, we need to understand ee
the terms and decipher the graphs Fr
much of this research is couched in. -.005
Shrinkage
The most typical diagram one might
find will show some form of a stress-
strain curve, which is simply a way
to measure how strong and flexible a -.01

material is, and when it is liable or
Temperature (¼F) Humidity (RH%)
to break.
In the first diagram on page 1
(Figure 1) the curved line represents Figure 2: An example of a simple Free Swelling Strain graph.
the typical behavior of many materials
when being stretched. At first the line
A second and more basic graph part paintings done on these materials
rises steeply as a build-up of force
(Figure 2) shows the percentage have survived in far better condition
is required to overcome its initial
of swelling or shrinkage a free, than others. An inflexible support will
resistance and begin to elongate.
unrestrained film of material essentially help restrain the potential
Think about the effort one might
experiences when responding to movements of the materials in response
need to initially lengthen a plastic
changes in either temperature (°F) to environmental changes or physical
grocery bag by pulling at it with
or relative humidity (RH%). By handling. Even today, this remains the
both hands. At first there is a sense
‘unrestrained’ it is understood that single most important piece of advice
of resistance but eventually, once a
the material is not inhibited in any anyone can offer for creating a durable
person is pulling hard enough, the
way from growing or contracting in oil painting with the least risk of
bag will begin to stretch for a ways
size. For example, imagine a piece of cracking or delamination. This is true
until eventually it reaches a breaking
loose fabric or wood that swells and whether the painting is done solely
point. If instead of a grocery bag one
shrinks as the relative humidity in with oils or on top of acrylic grounds
grabbed hold of an older, 12” long
a room varies. By measuring these and paints.
film of oil paint, one might be able to
dimensional changes we can quantify
stretch it just a 1/16”-1/8” before it Complications arise the moment
just how responsive the material is. If
broke, while many acrylic paint films we turn our attention to paintings
we now imagine this same material as
can elongate to twice their length or done on stretched cotton or linen
restrained in some way, say as a piece
more in ambient conditions, so quite since these materials are not simply
of stretched canvas, we can sense how
a difference. The amount of force more flexible but generally far more
the amount of tension will rise and fall
one needed in order to elongate the responsive to environmental changes.
as the canvas tightens and slackens,
material is called the ‘stress’, while the Traditionally, as a way to stabilize the
swells and shrinks, even though its
percentage the material stretches is fabric and protect its fibers from the
outermost dimensions stay the same.
known as the ‘strain’. A final concept harmful effects of oils, a size of hide
In this way the measurement of free
that is important to know is called the glue would be applied, followed by an
swelling strains are directly related to
‘yield point’. This is the point when oil ground and finally, the actual paint
the amount of stress generated in a
a material is stretched so far it can itself. However, this seemingly simple
painting whenever there are changes
no longer return to its original shape sandwich of materials (canvas, glue,
in the environmental conditions.
and so is permanently deformed or ground, paint) also generates highly
damaged. For a wide range of artist An Ideal Substrate complex interactions and divergent
materials and supports this is set at the forces as they age and respond to the
For oil painting, an ideal substrate
extremely low level of just one half of world around them. This area has
should be more rigid than any of the
one percent (.5%) and represents not been the focus of a wealth of
subsequent grounds or paints that lay
only a practical limit but shows just contemporary research and those
on top. Traditionally wooden panels
how little an amount of strain is findings can help us look at the
and sometimes even copper plates were
ever acceptable. viability of acrylics as a component of
used for this purpose, and for the most
an oil painting’s structure.
Issue 24 page 2 ©2011 Golden Artist Colors, Inc.
of the many examples generated
0.03 by Marion Mecklenburg, Senior
Research Scientist at the Smithsonian
Hide Glue
Institution, in order to make
(10 Years Old)
0.02 comparisons more easily. This diagram
Yellow Ochre Oil Paint shows typical free-swelling strains in
(20 Years Old) relationship to relative humidity for
ns 0.01 acrylic paints versus some common
ai
Str materials used in oil paintings.
g Lead White Oil Paint
ellin 0 A(2c0ry Ylieca rPs aOilndt)s (10 Years Old) As we can see, over a very broad
w range of humidity, the 20 year old
S
ee Traditional Chalk Gesso Acrylic Paints could swell or shrink
Fr-0.01 by a total of about 1.5%, which
is not widely different from the
approximately 1% response found in
-0.02 traditional chalk gessoes, which are
often considered one of the more stable
grounds to work on. Hide Glue was
-0.03 by far the most responsive, showing a
0 20 40 60 80 100
significant dimensional change of more
Relative Humidity (%)
than 4%, leading many researchers to
Figure 3: Amount of swelling due to changes in humidity for Acrylic Paints, Traditional Chalk Gesso, Hide identify this material as a major factor
Glue, and both Lead White and Yellow Ochre Oil Paints. Data adapted and simplified from Marion
in the cracking and delamination seen
Mecklenburg (2007a, 2007b)
in many older works. The Yellow
Ochre is representative of more
By far the widest use of acrylics under what circumstances? Fortunately reactive oil paints made with earth
under oils is as a replacement for in answering these questions we colors rich in clay and can rise almost
traditional grounds, and increasingly can draw from a significant body of 3% overall, with almost two-thirds
for fast drying underpaintings and research that has quantified how a wide of that occurring just within 60-80%
textures as well. Certainly a large part range of materials might respond to RH. This is far more movement than
of this trend is because acrylics are environmental changes, with a focus seen in the acrylic film and a very
seen as convenient and easy to use, as on humidity and temperature real cause for concern when looking
well as a desire to lessen exposure to in particular. at how oil paintings might respond
solvents. However, along with these Humidity to changes in humidity as many of
positives, questions and concerns have these earth colors will be vulnerable to
dogged their use from the beginning In Figure 3 we have combined flaking and delamination as a result.
and are generally grouped around three and simplified in one graph some Among the least responsive colors
areas: the potential problems caused
when materials respond differently to
environmental changes, worries about 0.01
adhesion, and the fact that acrylics are
inherently more flexible than oils. We
explore each of these in turn.
0.005
Responsiveness to Environmental
s
n
Conditions ai
It is often thought that a critical ng Str Hide Glue
danger of using oils on top of acrylics elli 0
w
is the potential for acrylics to swell S
e
or contract at rates so significantly Fre Oil Paints
Acrylic Paints
different from oil paints and mediums
-0.005
that it would cause the overlying
films to crack. This “fact” has been
repeated so often and gone unqualified
for so long that it has emerged as an
-0.01
unchallenged and generally accepted -40 -20 0 20 40 60 80 100
commonplace. In the process many Temperature, F¼
people forget to ask if acrylics actually
do, in fact, have such a different Figure 4: Degree of swelling in response to temperature changes for Oil Paints, Acrylics, and Hide Glue.
Data adapted and simplified from Marion Mecklenburg (2007a, 2007b)
dimensional response? And if they did,
Issue 24 page 3 ©2011 Golden Artist Colors, Inc.
are the various whites in oil paints, cracking at both moderate and lower Adhesion
such as the illustrated Lead White, temperatures. One recent investigation
The second major concern for
which typically stays well within a that focused primarily on alkyd and
most artists is simply whether oils can
very tight range of .5% or less. Along acrylic-based grounds, went so far
develop good adhesion to a range of
these lines, it is interesting to note as stating fairly unequivocally that
acrylic grounds, paints and mediums.
that a recent study (Hagen, 2006) “alkyd-based oil primers present
This is an area GOLDEN began to
has shown matte latex housepaints the most vulnerable type of primer
look into more than 15 years ago, and
containing high levels of solids for contemporary flexible supports”
what follows is a review of those results
respond far less to moisture than even (Young, Hagen, 2008). Even at such
as well as a look at some conservation
this, to the point of being essentially moderate temperatures as 68°F (20°C)
studies that focused on the adhesion of
inert to even extreme changes in the study found that a linseed oil-
oil paints containing zinc oxide.
humidity. If nothing else, this has based lead carbonate ground fractured
reinforced our belief that matte when stretched as little as 1.6%, The first round of testing GOLDEN
acrylic paints and gessoes, which while the most flexible of the alkyd- conducted was in the mid 1990s and
share many of these traits, could based grounds was able to sustain involved creating 10 mil drawdowns
provide very stable surfaces for oils to 9% elongation. However, by 50°F of five oil paints (Indanthrone Blue,
adhere to and further investigations (10°C) those levels had dropped to Ultramarine Blue, Mauve Blue Shade,
along these lines should be pursued. .8% and 2.1% respectively. At 32°F Cobalt Turquoise, and Cobalt Blue
(0°C), the lead white ground showed Deep) over three distinct types of
Temperature
failure with just .4% strain, a level that acrylic films: GOLDEN Gesso, Heavy
In contrast to humidity, can easily be expected with normal Body Titanium White, and a mixture
dimensional changes brought about handling and movement. By contrast, of two parts Self Leveling Clear Gel
by fluctuations in temperature are GOLDEN Acrylic Gesso recorded a to one part Fluid Titanium White.
extremely minimal and would pose failure strain of 1% even at the much This provided examples of a matte
almost no threat by themselves, lower temperature 14°F (-10°C), while and toothy ground, a standard acrylic
which is not surprising given how few at 32°F it could still stretch 2.3% paint, and a very smooth and glossy
of these materials would be expected before fracturing, and by 50°F it had layer of a tinted acrylic medium. There
to appreciably swell or contract due a strain-to-failure of 7.3%. This type were 75 samples created, with 25
to temperature alone. In general of dramatic embrittlement of oil- on top of each of the three different
oils, acrylics, and hide glue can be modified alkyds was also noted in both coatings. The samples were done on
expected to remain within a narrow past and current research (Erlebacher, lacquered cards and kept in moderate,
.5% range. The graph on page 3 1992, Ploeger, 2009, Alba, 2010), ambient conditions within the Lab
(Figure 4) shows a simplified view where acrylics have consistently been facilities. Adhesion tests were carried
of free swelling data that would be shown to have a greater ability to out in accordance to ASTM 3559
considered typical over a range elongate at low temperatures. and a few representative samples were
of temperatures. aggressively flexed to the point of
To make the sense of concern more
causing substantial cracking to see if
What is far more problematic is concrete, and as a way to visualize
the paint could then be cleaved off
the increased embrittlement shared the degree of strains we are talking
with the use of a scalpel. So far there
by oils, alkyds, and acrylics when about, a 25”x30” painting would only
has not been even one recorded case of
subjected to low temperatures. need to be keyed out a scant 1/16”
failure, even when the oil paints were
Unlike the minor degrees of swelling to sustain a 1% or higher diagonal
applied over very smooth and high
or contraction we just saw, extreme strain in the corners and a .5% strain
gloss films.
embrittlement can put a painting at when measured across the short side.
very high risk of fracture due to the This means that even at the moderate A second and much broader round
build up of internal stresses alone, temperature of 50°F, some of the oil of testing was started in 2006 and
not to mention the mechanical primers included in the above study included 99 samples, each consisting
stresses experienced during any would be at risk of cracking. of a 10 mil drawdown of oil paint
amount of stretching, handling over an equal thickness of GOLDEN
While follow-up studies will
and transportation. What has been Gesso. The oil paints included three
ultimately be needed, for now at least
surprising, however, is just how colors (Yellow Ochre, Burnt Umber
it appears that some acrylic primers,
well acrylics have performed given and Ivory Black) from three different
such as GOLDEN Acrylic Gesso,
how they generally begin to stiffen professional brands applied straight
could provide a foundation that is less
dramatically below 50°F (10°C). In from the tube, mixed 3:1 and 1:3 with
prone to fracture when temperatures
fact, several studies comparing acrylic an alkyd medium, blended 4:1 with
are 50°F or lower. That said, we still
primers to current oil-based grounds, bleached beeswax, and finally, thinned
believe low temperatures present
including ones based on oil-modified 1:4 with odorless mineral spirits
extremely high risks for all the paint
alkyds, have shown that the acrylic and applied by brush as a thin wash.
systems covered and great caution is
primers provided distinct advantages Following these applications, final or
urged before subjecting any artwork to
when looking at how much they retouch varnishes made from damar or
these conditions.
could be flexed or stretched before GOLDEN MSA Varnish were applied
Issue 24 page 4 ©2011 Golden Artist Colors, Inc.
at different intervals. Crosshatch problem that went beyond the specific risks imposed on the structure are
adhesion tests have subsequently been issues tied to zinc oxide itself, we from the forces generated by the
conducted and found no case was a would expect to see multiple failures traditional hide glue sizing in
failure ever found. As in the prior test, occurring in these other samples as response to humidity and the equally
all the samples will continue to be well. The conclusions in these studies dangerous enbrittlement caused by
monitored and retested over time. were further amplified by a study low temperature.
on the cracking and delamination
While our tests should begin to Sizing
found in works by various Abstract
provide some confidence in the
Expressionists where zinc oxide oil While hide glue continues to attract
ability of oils to adhere to a wide
grounds were used (Dawn et al, 2010). a lot of devotion from those working
range of acrylic films, concerns have
The fact that these issues were found with traditional materials, the evidence
also been raised recently about some
in numerous examples completely pointing to its weaknesses and role in
well-publicized studies focusing on
unrelated to acrylic grounds further the cracking and delamination of paint
the delamination of oil paints from
emphasizes that the problem resides in films is substantial and convincing. Its
a variety of acrylic grounds (Maor,
a structural weakness tied to zinc-rich one feature of merit, the exceptional
Murray 2007, Maor et al 2008,
oil paints independent of other factors. strength it provides when kept
Maor 2008, Mecklenburg 2007b).
within precise humidity ranges, is
The investigations have primarily Flexibility
quickly overshadowed by its extreme
been based on test samples created in
As was mentioned, the simple hydroscopic nature and the fact that it
1999 by Marion Mecklenburg at the
fact of painting on stretched fabric quickly loses all strength above 75%
Smithsonian Institute to specifically
presents a problem for the oil painter RH and is no longer able to carry
explore this issue, as well as two actual
who knows their paints will grow the amount of tension inherent in a
paintings where cases of delamination
increasingly brittle with age while stretched canvas.
had occurred. In looking at the
the cotton or linen continues to
results, it is critical to remember that Given these problems, it is natural
flex and strain, tighten and sag, just
ultimately the studies concluded that to want to find a viable substitute for
a few millimeters underfoot. The
the presence of significant levels of hide glues altogether. GOLDEN GAC
movements and stresses of a fabric
zinc oxide was the root cause of the 400, an acrylic product, has long been
support have been well charted by such
delamination and not the fact that the recommended since it helps to stiffen
researchers as Gustave Berger, Gerry
grounds were acrylic based. As Yonah canvas. More work definitely needs
Hedley, and Marion Mecklenburg.
Maor states, when summarizing her to be done before one can claim to
What has developed from much of
results: “The determining factor is have formulated an ideal substitute,
these investigations is the fact that, as
the metals present in the oil paint and especially when providing a sufficient
counterintuitive as it is, it is not the
not the type of ground.”(Maor, 2008) degree of stiffness for even the
canvas but the more rigid sizing that
The actual mechanisms of how various oldest, most brittle films of oil paint.
supports the overlying ground and
metallic soaps which formed in the However, when we look at the amount
paints, and that by far, the greatest
affected paints, and specifically those of stiffening it does accomplish, one
from zinc, caused embrittlement and
delamination are still being worked
25
out, although it appears that build-up Yield Point
2 coats
of the soaps at the interface between 2 coats GAC 400 (Þll)
the paint and the ground was a Hide Glue (Þll)
20
consistent factor. It was also noted that
rougher grounds appeared to provide
h)
better adhesion than smooth ones, nc
lbeen adbinleg tsoo mleses ehno pthee tihr artis akr tbisyt sc hmoiogshint g dth (lbs/i15 Z1(15in50 c Yy eeWaarrh soi Otldel d leO, aaidcl t wsP haliikitnee) t GAC 24 0c0o a(twsa rp)
grounds that are particularly toothy. wi Lead White Oil Paint
At the same time, it is important to e per 10 (1l5ik Yee 5a0rs y Oealdr, owldit hw hdirtiee rl,e aacdt)s 2 coats
recognize that more than 16 paints orc Hide Glue (warp)
(out of a total of 20) that contained F
no appreciable levels of zinc also
showed no delamination whatsoever 5
and represented a broad selection of
Lead White Oil Paint
pigments, including titanium dioxide, (15 Years Old)
lead carbonate, raw sienna, cobalt blue, 0
0 0.005 0.01 0.02 0.03 0.04
ultramarine blue, red oxide, yellow
Strain
ochre, terre verte, indian red, burnt
Figure 5: Stiffness of two coats GAC 400 on linen compared to Hide Glue and 12.5 mil thick oil paint
sienna, burnt umber, and verdigris.
films of Zinc White as well as Lead White, with and without drier (50.8% RH, 72.5 ºF). Data adapted
Certainly if there was a systematic from testing done by Marion Mecklenburg, Senior Research Scientist, Smithsonian Institution, Wash., D.C.
Issue 24 page 5 ©2011 Golden Artist Colors, Inc.
can see that it comes close to equaling
the stiffness of hide glue at ambient 4
Yield Point
conditions. Figure 5 (page 5) presents
Lead White Oil Paint
a graph from testing done by Marion (14.25 Years old)
Mecklenburg showing 2 coats of GAC Zinc White Oil Paint
400 applied to linen versus 2 coats 3 (14.5 Years Old)
of hide glue, alongside results from
cast, free films of oil paints with a film Pa) Acrylic Gesso
thickness of 12.5 mil. M
s (2 Titanium White Oil Paint 4 Coats
The main drawbacks of GAC 400 es (14.5 Years Old)
is that it still falls short of the stiffness Str
found in very old oil paint films, or
even younger ones made with brittle Naples Yellow Oil Paint Acrylic Gesso
1
pigments like zinc oxide, and in order (12 Years old) 1 Coat
to be fully water resistant at higher
humidities it needs to be heat set by
Raw Umber Oil Paint
passing a hair drier set on high over the (12.25 Years Old)
0
surface for several minutes. However, 0 0.005 Y e llow Ochre 0.02 0.03 0.04
given that hide glue is so much more (12.25 Years Old)
Strain
reactive, these trade-offs are something
to consider if the piece will not be Figure 6: One and four coats of Acrylic Gesso compared to variously aged oil paints at ambient
permanently kept under tightly conditions. Data adapted from testing done by Marion Mecklenburg, Senior Research Scientist,
Smithsonian Institution, Washington D.C.
controlled conditions.
Acrylic Grounds: Impact of
different. A thin film of acrylic paint flexibility of acrylic grounds. In
Thickness, Composite Structure,
will act differently, from a practical recently published research looking at
and Flexibility
standpoint, than a substantially thicker composites of various grounds paired
When thinking about the degree of one; a thin layer of medium differently with various paints, a professional oil
flexibility that acrylic grounds have, then a 1/4” thick slab of gel. paint applied to GOLDEN Gesso
many people fall into the trap of proved extremely flexible, with
We see this effect at a small scale in
thinking of a stretchy rubber-like film no fracture observed even at 20%
the diagram above (Figure 6), where
with brittle paint applied on top, then elongation and after subjecting the
four coats of Acrylic Gesso begins to
imagining that film being stretched piece to 100 folds. This was performed
have the stiffness of older films of basic
until the paint cracks. But of course on a relatively ‘young’ oil paint film
lead carbonate, and certainly remains
this is a spurious image at best simply of 2 years and it would be expected
stiffer than many other colors, such
because it has no practical relationship that with time the oil paint will
as Naples Yellow, Raw Umber and
to the actual levels and types of embrittle and such degree of flexibility
Yellow Ochre.
stresses and strains a painting is likely will be more unusual. Even so, it is
to encounter. It is an image taken Composite materials are also instructive to compare this to the same
to a point of excess and caricature. complicated in other ways. An acrylic oil paint on an oil-modified alkyd
Far more important is to understand gesso that normally by itself might ground where cracking occurred when
how stiff or resistant to elongation a be able to elongate more than 100%, stretched 11.6%. As the oil paint is the
material is and to realize that being stiff when applied onto a fabric support same, the performance appears to be
does not necessarily mean a material is that can be stretched a maximum of strongly correlated to the more brittle
brittle. As an example, most metals can 31%, doesn’t all of a sudden increase underlying ground layer. Further
be bent and elongated; it simply takes the stretchiness of the fabric but, comparison of the performance of
a lot of force to do so. Or think of the perhaps unexpectedly, reduces it even flexible acrylic gessoes versus stiffer
impact that thickness alone can have further, to a mere 12%, due to locking alkyd grounds can be seen when
on how we think about these ideas. the fibers in place and thus stiffening considering their performance when
Many materials, for example, can come the flexible fabric even further (Young, alkyd paints are applied on top of each.
both as thin films and as thick sheets Hagan 2008). This effectively sets an As the authors of the study concluded,
or boards, with very differing amounts upper limit of how much elongation the “acrylic primings reduced the
of resistance to being stretched or any acrylic film might have when amount of cracking in the alkyd top
deformed. A very stretchy plastic wrap applied to a canvas support. And of layers, appearing to retard their normal
and a stiff cutting board can be made course even this limit would never be brittle behavior.” If nothing else, these
from the same type of plastic, but reached in response to environmental results suggest areas for new research
we think of them very differently if changes or reasonable handling. into the possibility that flexible
worried about how flexible they are as A last point to bring up heads in a primings could actually have beneficial
painting supports. And acrylics are no very different direction altogether and effects through some form of interfacial
sees potential benefits in the inherent dynamics or stress reduction.
Issue 24 page 6 ©2011 Golden Artist Colors, Inc.
Conclusion Bibliography
So, in the end, the question Alba, Ana, Susan Lake, Mel and Scientific Methods to Evaluate
remains: can one safely use oils on Wachowiak, 2010, A Question of their Effectiveness. Proceedings of the
top of acrylics? And if so, what are Technique: Condition Issues Associated Conference, Milan, Saonara, Italy: il
the guidelines and best practices? We with Layering Structure in Richard Prato, pp.49-58
believe some concerns are overblown Diebenkorn’s Ocean Park Series, AIC Mecklenburg, Marion F., 2007a,
in the public’s mind, and not a cause Conference Paper Determining the Acceptable Ranges of
for alarm, such as the amount acrylics Erlebacher, Jonah D., Eric Brown, Relative Humidity and Temperature in
might swell or shrink in response Marion F. Mecklenburg, and Charles Museums and Galleries, Part 1, Structural
to normal environmental changes. S. Tumosa. 1992. The Effects of Response to Relative Humidity, http://
Other areas, however, clearly warrant Temperature and Relative Humidity on eprints.sparaochbevara.se/165/.,
additional research to fully understand, the Mechanical Properties of Modern 1-57. (http://si-pddr.si.edu/dspace/
such as the extreme brittleness Painting Materials. In Materials Issues handle/10088/7056)
displayed by alkyd and oil grounds at in Art and Archaeology III: Symposium Mecklenburg, Marion F., 2007b,
lower temperatures when compared Held April 27-May 1, 1992, San Determining the Acceptable Ranges of
to acrylic-based ones, or the apparent Francisco, California, U.S.A, ed. Pamela Relative Humidity and Temperature in
ability of acrylic grounds in some B. Vandiver, James R. Druzik, George Museums and Galleries, Part 2, Structural
cases to lessen the brittleness of alkyds Segan Wheeler, and Ian C. Freestone, Response to Temperature, http://eprints.
and oils applied on top. We continue 359-70. Materials Research Society sparaochbevara.se/165/., 1-29. (http://si-
to believe that adhesion of oils to Symposium Proceedings. vol. 267, pddr.si.edu/dspace/handle/10088/7055).
Pittsburgh, Pa.: Materials Research
acrylics per se is not a concern, while Ploeger, Rebecca, Dominique
Society.
also recognizing that the problems Scalarone, Oscar Chiantore, 2008,
being seen with oil-based products Hagan, Eric, Maria Charalambides, The Characterization of Commercial
containing zinc oxide is very real and Thomas J. S. Learner, Alison Murray, Artists’ Alkyd Paints, Journal of Cultural
should lead painters to excercise great Christina Young, 2006, Factors Affecting Heritage, Vol. 9, Issue 4, pp. 412-419
the Mechanical Properties of Modern
caution when using any of these paints.
Ploeger, Rebecca, Dominique
Paints, Modern Paints Uncovered, Getty
Indeed, in response to the research
Scalarone, Oscar Chiantore, 2009,
Conservation Institute, pp. 227-235
coming out, we have adjusted some Thermal Analytical Study of the Oxidative
Williamsburg Handmade Oil Colors Learner, Thomas, 2004, Analysis of Stability of Artists’ Alkyd Paints, Polymer
to lower the percentage of zinc oxide Modern Paints, Getty Publications, Degradation and Stability, Vol. 94, pp.
in those mixtures where it is used, or Canada 2036–2041
eliminate it all together when possible. Maor, Yonah and Alison Rogala, Dawn, Christopher Maines,
For now what constitutes a “safe level” Murray, 2007, Delamination of Oil Marion Mecklenurg, 2010, A Closer
of zinc is simply not known, and any Paints on Acrylic Grounds, Materials Look: Condition Issues in Abstract
level is merely a best-guess. While Research Society Meeting, Materials Expressionist Ground Layers, AIC PSG
we have currently adopted 15% as a Issues in Art and Archaeology VIII, Postprints 22
maximum, we also recognize future Symposium, Proceedings Volume 1047,
Young, Christina, Rebecca Gregg,
testing is needed for full confidence. Materials Society (MRS) Fall Meeting,
Roger Hibberd, James Walker and Tom
Other things point to opportunities Boston, November 2007 (Warrendale,
Learner, 2004, The Physical Properties of
for updating our guidelines, such as PA: MRS, 2008) 1047-Y04-01
Modern Commercially Available Primings
applying multiple layers of an acrylic Maor, Yonah, Alison Murray, Bruce and Their Interaction with Subsequent
ground to achieve more stiffness, Kaiser, 2008, Using XRF for Semi- Paint Layers, Modern Art, New
or simply reaffirmed long standing Quantitative Analysis in a Study of Museums, Contributions to the Bilbao
recommendations, suuch as the Delaminating Paint, 9th International Congress, p.244
benefits of a toothy surface for assuring Conference on NDT of Art, 25-30
Young, Christina, 2006, Interfacial
maximum adhesion. And lastly, there
Maor, Yonah, 2008, Delamination of Interactions of Modern Paint Layers,
are areas where we recognize that
Oil Paint from Acrylic Grounds, Master’s Modern Paints Uncovered, Getty
improvements can be made, such as
Thesis, Queen’s University, Canada Conservation Institute, pp.247-256
formulating an even stiffer size that
can block oil while fully maintain the Mecklenburg, Marion F., 1990, Art Young, Christina, and Eric Hagan.
tension of stretched fabric, even at in Transit: Studies in the Transport of 2008. Cold Temperatures Effects on
higher humidities. Paintings, Washington, DC: National Modern Paints used for Priming Flexible
Gallery of Art Supports. In Preparation for Painting: The
Visit www.goldenpaints.com/
Mecklenburg, Marion, Matteo Rossi Artist’s Choice and Its Consequences, ed.
technicaldata/techsheets.php for
Doria, Laura Fuster Lopez, 2006, Joyce H. Townsend, Tiarna Doherty,
updated Product Info Sheets on best Failure Mechanisms in Canvas Supported Gunnar Heydenreich, and Jacqueline
practices for using oils over acrylics and Paintings: Approaches for Developing Ridge, 172-179. London: Archetype
other issues related to acrylic grounds.
Consolidation Protocols, In: CESMAR
7, The Care of Painted Surfaces.
Materials and Methods for Consolidation,
Issue 24 page 7 ©2011 Golden Artist Colors, Inc.
Make a Mark the surface. Drawing has an immediacy
ASTM NEWS and nostalgia that few other mediums
have. Drawing speaks to our human
By Sarah Sands
nature and our desire to communicate
By Amy McKinnon
With a healthy dose of self-deprecating and express, it is the visual outcome of
humor, ASTM members often declare Make a mark, erase it? Can you? what our minds tell our muscles. The
that its well-known acronym actually Is it permanent? Will it remain with use of drawing material allows an artist
stands for “Awfully Slow and Tedious
stubborn pride? Will it all wipe away a mark unattainable and separate from
Method,” and if gauged simply from
except for a stain that tells of its past? that made with a brush.
the standpoint of the time it takes to
Will it disappear as if it had never
complete a Standard, one can see their If you happen to work in a manner
point. The ASTM Standard for Acrylic been there? Was it ever there? Will it
in which your supply cabinet is
Dispersion Grounds started 7 years smudge and spread like a tumultuous
your palette you have most likely
ago, under the guidance of its original rumor imbuing itself into everything
encountered unexpected interactions
task chair, Bill Berthel of GOLDEN. it comes in contact with? Will it be
In 2008 those reins were passed to me, between materials, some being pleasant
blown away in particles by a breeze
with faith the committee would see the discoveries others being less than ideal
from a space between the floor
job to the finish. If all goes as planned, solutions. Acrylics can offer a stable
boards? Will it hold in some areas
this Standard will be approved by the support on which a wide variety of
Subcommittee on Artists’ Paints and and crawl away from the surface in
drawing media can be applied although
Related Materials (D01.57) late January, others? Will it rip apart and destroy
some acrylics can be more accepting
and by the ASTM body, sometime the surface as you use it? Mark it,
than others. We prepared a variety of
that spring. Thank you to all who so stroke it, smear it, smudge it, hatch
tirelessly helped along the way, as this acrylic surfaces and applied numerous
it, blend it, stipple it and scribble it.
work can only happen with cooperation drawing media to those surfaces to
Any way it is applied, artists are often
from the entire committee. We would evaluate how the media held to the
compelled to incorporate drawing
like to single out Bill Berthel, Mark surface. Once we saw how the acrylics
Gottsegen, Karyn Meyer-Berthel, and the into their paintings. Painting, even
accepted the drawing media we altered
Committee Chair, Michael Skalka, for in the most expressive manners, can
the marks made to see how they
their humor, patience, and willingness feel so planned out and calculated in
reacted to manipulation.
to participate in the round-robin testing comparison to charcoal in the hand to
the Standard is based upon. The hope What we found was that
is that conformance to this standard
Finger Water Alcohol the vast majority of drawing
will provide artists with confidence that
Rub Wash Wash media could be used over a
acrylic dispersion grounds and primers s s s
will meet minimum thresholds for sSharpie® number of acrylic surfaces.
flexibility, adhesion, and the ability to The majority of marks we
sIndia Ink
block oil strike-through. Currently no made held to the surface.
such standards exist and artists have no We found that measuring
sCopic® Sketch Marker
means of gauging performance before the acrylic surfaces in terms
purchasing this essential material that sCopic® Sketch Marker of hardness and tooth
artwork is entrusted to.
sPigma Brush Pen was a telltale sign of how
While this chapter is coming to a
media would work upon it.
close, work on a pre-primed canvases sOil Pastel
standard is already underway. In 2007, Whether hard or soft, acrylics
sChalk Pastel
when GOLDEN published a Just with tooth appear to provide
Paint article highlighting the potential sCaran d’Ache NeocolorTM a good adhesive surface for
problems of acrylics adhering to some most if not all the drawing
pre-primed canvases, we expressed sWater Soluable Oil Pastel
media we tested (Fig. 1a,
our hope the ASTM Subcommittee
sPastel Pencil 1b). An acrylic film that
would establish minimum performance
possesses a combination of
and quality standards for these critical
sWax Crayon
products. In the last year, the work has hardness and tooth provides
taken shape under the leadership of Task a surface that on much closer
sSanguine Pencil
Chair, Rick January of Tara Materials, inspection, resembles a micro
with assistance from Mark Gottsegen sConté Crayon landscape of jagged rocks.
of AMIEN, Sarah Sands of GOLDEN,
As something is dragged
and Michael Skalka, Conservation sGraphite 9B
or pushed over that surface
Administrator for the National Gallery
much of that material would
of Art as well as the Subcommittee’s sGraphite 5H
Chair. While much still lies ahead, we are be snagged and remain on
confident the team is in a good position sGraphite 2B that rough terrain.
to build on the accomplishments that
sCompressed Charcoal The textures of the hard
have culminated in the ASTM Standard
and toothy surfaces range
for Acrylic Dispersion Grounds. And
you never know, perhaps even to do it in sVine Charcoal from Fiber Paste to Fine
record time. Pumice Gel. Fiber Paste
(Fig. 2a), which resembles
Issue 24 page 8 ©2011 Golden Artist Colors, Inc.
Figure 1a: GAC 200 is a good example of a hard, smooth surface. Figure 1b: Acrylic Ground for Pastels displaying a hard, toothy surface.
Figure 2a: Fiber Paste exhibits a broken line when drawn upon. Figure 2b: Fine Pumice Gel allows for a continuous line when drawn upon.
Figure 3: Wet Media on Regular Gel (Gloss). Figure 4: Glass Bead Gel tended to hold wet media within its crevasses while
allowing the tops of the glass beads to be wiped clean.
handmade paper when drawn upon, sometimes proved to be a fugitive glass bead and granules to be wiped
will exhibit a broken line due to marriage. The glossy and hard surfaces clean (Fig. 4). Glossy and soft surfaces
a rough texture as opposed to a accepted most media applied to it but provided enough tack to have
continuous line achieved with Fine when rubbed or wetted much of the slightly better adhesion than a glossy
Pumice Gel (Fig. 2b). The thicker and media could be removed. The surface hard surface.
softer films have a greater susceptibility was too slick to provide adhesion. It
When looking at the media used for
to damage from harder media. For did however, support the hardest of
drawing, the possibilities are almost
example, Light Molding Paste and the graphite pencils, which etched
endless. We chose to look at some
Crackle Paste, which both lend and marred many of the softer acrylic
of the more common options that
themselves to thicker application, will films. The texture of hard, glossy
artists may use. We tested vine and
provide a fine, soft surface for vine surfaces sometimes provided a unique
compressed charcoal, 5H, 2B and 9B
charcoals and dry pastels but media tooth that allowed for interesting
graphite pencils, Conté® crayons,
like graphite and Conté® crayons manipulation with the wetter and
sanguine pencil, wax crayon, pastel
will etch the acrylic surface without softer media. An example of surfaces
pencil, water soluble oil pastels, water
imparting any actual media. like this would be Glass Bead Gel or
soluble colored pencils, dry pastels,
Clear Granular Gel which seems to
Smoother and glossier acrylic oil pastels, markers, and inks. Each
simultaneously provide a non-porous
surfaces held wetter media better than was applied in a series of short strokes
surface with a toothy texture, which
that of dry (Fig. 3). Markers, inks over 24 acrylic surfaces. The nature
held media within the crevasses of the
and oil based media were applied of how each behaved when applied
film but allowed the glossy tops of the
easier but manipulation of that mark and adhered to the acrylic surface was
Issue 24 page 9 ©2011 Golden Artist Colors, Inc.
Figure 5: Coarse Molding Paste washed with water (left) and alcohol (right). Figure 6: Absorbent Ground received all media and allowed for easy manipulation.
noted. Each piece of drawing media textures and surfaces, hardness and The drier and more friable media,
was applied in a series of small strokes softness but all contained opacity and a like charcoal and pastels, were able to
to each of the 24 acrylic surfaces and fair amount of porosity and tooth. be blended and smudged evenly and
then manipulated by rubbing, washing maintained adhesion to the Absorbent
The drawing media could be
with water or washing with alcohol. Ground. The sponge-like absorbency
grouped based on a number of
The initial drawn marks were observed without the flexibility afforded by the
different criteria: hardness and softness,
for how they lay on the surface, how Absorbent Ground allowed for the
the base or pigment, the vehicle or
they responded to the texture of the water and alcohol to disperse some of
lack thereof or how it responded to the
acrylic and how they held to that the marks into a wash without entirely
paper. It presents itself as being most
surface. The rubbed area served two obliterating the original mark.
logical to group the drawing media on
main purposes: to see if the media In the case of the waterproof inks,
its hardness and softness followed by
could be removed by mechanical the alcohol was the most effective in
its vehicle. Utilizing grouping by the
rubbing or if it would adhere and how creating a wash, as the water left the
vehicle or its solvent is only applicable
it responded to blending or smudging? mark unaffected.
if the vehicle/solvent is presumed to
Did it blend seamlessly? Did it leave a
be the catalyst when manipulated. The
trace of the mark made? Or, did it not
charcoal (vine and compressed) and
do anything? The area washed with
the sanguine pencil made up the first
water showed how the media reacted
group. The second group was the 5H,
to water, how it dispersed, and how the
2B and 9B graphite pencils and the
wet media was accepted to the acrylic
Conté® crayons and wax crayon, the
surface. The area washed with alcohol
third. The fourth group was the oil
showed the solubility of the media and
crayons and oil pastels, while the fifth Figure 7 Coarse Molding Paste Washed with Water
how it reacted with the acrylic surface, (left)nd Alcohol (right).
group was made up of the water based
how it dispersed and if it changed the
or water soluble colored pencils, chalk
nature of the media (Fig. 5).
pastels and pastel pencils. The sixth
We applied the drawing media to group contained all the wet media, Figure 7: The harder, less porous surface of burnished
24 different acrylic surfaces. Those including markers and inks. Sandable Hard Gesso allowed for sharp, crisp lines.
surfaces can be roughly grouped into
The GOLDEN Acrylic Grounds The Gesso, Sandable Hard Gesso
six different categories based on their
used for this testing were Gesso, and synthetic chalk ground reacted
characteristics. The first is a group of
Sandable Hard Gesso, Absorbent similarly with only slight variations
grounds, which are surfaces that are
Ground, Silverpoint / Drawing to one another. The Sandable Hard
typically absorbent and toothy and
Ground, and a mixture of one-third Gesso was wet sanded to a burnished
formulated to accept a wide variety of
Gesso, one-third Light Molding finish before the media was applied.
materials. The next group is acrylic
Paste and one-third Hard Molding The harder, less porous surface allowed
paint in which we chose Fluid Acrylics
Paste (synthetic chalk ground). These for sharper and crisper drawn lines
as well as Matte Fluid Acrylics. The
grounds accepted all of the drawing (Fig. 7). When those drawn lines
third group included liquid mediums
media applied to them with no adverse were blended, the product was less
that dry glossy with a fair degree of
results. The more porous grounds likely to produce a soft edge and had a
hardness to their finish. The fourth
provided better blending. Absorbent better chance of removing the original
group consisted of very matte and
Ground, being the most absorbent mark. Being an absorbent and spongy
toothy surfaces. The fifth group was
without too much flexibility, allowed surface, the synthetic chalk ground
made up of soft and flexible films and
for not only a well received mark by all accepted more of the media than the
the final group was the pastes, which
media but also permitted the media other two, leaving a softer and wider
tended to offer the largest range of
to be easily manipulated (Fig. 6). mark. Blending the media on synthetic
Issue 24 page 10 ©2011 Golden Artist Colors, Inc.