Prior to actual use, it is very
important to experiment with Golden varnishes on test pieces to
become aware of how they perform and how they alter the surface
appearance of paintings. For best results, apply to a test piece
that is similar in composition as the artwork to be varnished.
This will help ensure that all variables are accounted for, and
a successful varnish application will be achieved.
Only intended for acrylic paintings, do not use on oil paintings.
For future conservation and varnish removal purposes we recommend the use of an isolation coat prior to varnishing. An isolation coat is a permanent, non-removable coating that serves to physically separate the paint surface from the removable varnish. This will help protect the surface if the varnish is ever removed and make future cleaning and conservation easier to avoid working directly on top of the pigmented part of the work. Therefore, even if painted with delicate washes or large areas of colors that could potentially bleed, a clear barrier would safely cover the painted surface. It will also seal absorbent areas, which will result in a more even application of the varnish. In the event that no varnish gets applied, the isolation coat serves to decrease the water sensitivity of the paint surface, affording protection during routine cleaning/dusting.
Given the current state of conservation science, we feel the use of an isolation coat provides the most protection. However, isolation coats are also significant and permanent additions to a painting and inevitably will cause changes in the painting's surface qualities. Whether these changes are acceptable is an aesthetic decision that each artist needs to make after sufficient testing. In addition, since it is non-removable, any mistakes or problems during this procedure cannot be easily corrected and there is always an element of risk that needs to be considered. We strongly encourage the artist to practice these procedures thoroughly so they feel confident and become familiar with any unforeseen problems. If you have any questions or concerns regarding the proper use or application of an isolation coat, please call Golden’s Technical Support Department at (800) 959-6543.
For brush application, the appropriate isolating medium can be made by diluting Golden Soft Gel Gloss with water (2 parts by volume Soft Gel Gloss to 1 part water). If a spray application is desired, a 2:1 mixture of Golden GAC-500 to Transparent Airbrush Extender can be applied with an airbrush, touch-up spray unit or commercial spray equipment. The absorbency of the surface will dictate the number of isolation layers required. For relatively non-absorbent surfaces, as is the case with a uniform paint layer, one coat brush applied or two coats spray applied are recommended. For more absorbent surfaces, which tend to be very matte, it is recommended to apply sufficient isolation coats to achieve a satin sheen on the surface. This may require two or more brush applied coats or three or more spray applications.
The isolating layer is of critical importance when applying a matte varnish over an absorbent surface to prevent a cloudy or "frosted" appearance from occurring. This frosted appearance results from the varnish and solvent being absorbed into the support, while the matting agent remains exposed on the surface. While we have carefully selected the matting agent that is in Golden varnishes to be as transparent as possible, it is still a dry particulate material. When the matting agent is deposited onto the surface, and is not a part of a continuous varnish layer, it appears as a white solid. If varnishing water-soluble paints, including watercolor, gouache and tempera, the isolation coat must be sprayed on in very light layers to avoid solubilizing the paints, which could cause loss of distinctness of the underlying image.
Make sure paints are sufficiently
dry. For acrylics and other water-based media, if the painting
is composed of thin layers, waiting a day or two before applying
the isolation layer, followed by another two days to a week before
varnishing, is recommended. If there are thick, impasto
areas of acrylic paint, wait a week or two before applying the
isolating layer or varnish. Oil paints generally require six months
to a year drying time prior to varnish application. Next, make
sure the surface the varnish is to be applied to is clean. It
should be free from dust which could affect appearance of the
varnish. If the isolation coat (over an acrylic painting) has
cured for more than 2-3 weeks, the surface should be washed with
water using a soft, clean cloth in order to remove surfactants
which may have migrated to the surface, as these can interfere
with adhesion. Allow the surface to dry completely before varnishing.
Another consideration is the ambient
conditions of the work area. Ideally, the temperature should be
above 65 F and below 75 F, while the relative humidity is between
50% and 75%. Excessive humidity or cool temperature may result
in bloom, a whiteness or opacity resulting from moisture trapped
between the varnish and paint layers. If the surface of the piece
being varnished is warmer than the varnish applied, the varnish
will become thinner in viscosity upon application. This may result
in unexpected dripping or sagging, particularly if working vertically.
Likewise, if the varnish and surface are relatively cool, but
warm significantly shortly after application, the varnish may
drip or sag. Prewarming the varnish in a warm water bath can help
The type of surface can
greatly impact how varnish is best applied. Stained or
partially coated surfaces are some of the most difficult to successfully
varnish, due to the uneven nature of their application. In areas
with a heavier stain, the varnish may sit on top, while sections
with more thinly applied paint, or no paint, will allow the canvas
to absorb the varnish into the fabric support. This discontinuous
surface can cause uneven saturation of the varnish, yielding a
blotchy appearance with non-uniform reflectance. Also critical
in the application of this sort of surface is the thinning of
the varnish and the amount of varnish on the brush. More thinning
and the varnish increases penetration. Too much varnish on the
brush in one area and the varnish gets absorbed and soaks through
the piece. An isolating layer applied before varnishing will provide
a continuous surface for the subsequent application of a uniform
final varnish layer. It is then possible to match the original
surface appearance by lightly applying matte varnish. The nature
of the surface must be considered when selecting the finish that
is desired. As mentioned in the isolation section, highly absorbent
surfaces must have an isolation coat applied before application
of a matte or satin varnish. Surfaces that need to be reflective,
such as the Iridescent and Interference Acrylics or metals, would
require a gloss varnish to maintain the reflective quality. Golden
varnishes are not intended for use on furniture, floors or other
surfaces where a high degree of physical toughness is required.
For applications such as these, the polyurethane family of resins
proves most useful. When selecting a polyurethane, note that aromatic
type urethanes yellow significantly, while the aliphatic
types do not.
Thinning GOLDEN Varnishes
Golden Varnishes must be
thinned before use. This reduces the film thickness applied
and the chance of uneven application. It also allows for much
greater fluidity of application, which is critical when applying
a varnish. If applied in a thick state, the varnishes may show
brush strokes and trap foam bubbles. The varnishes have been made
thicker for the purpose of maintaining an even suspension of the
solids within the varnish. Even slight settling of varnish solids
during storage may result in streaking within the dried varnish
Thinning GOLDEN MSA
In theory, mineral spirits, commonly
referred to as "paint thinner", should suffice to thin Golden
MSA Varnishes, however, they do not always work. "Odorless"
mineral spirits should NOT be used because they are not
strong enough to be compatible with the varnishes. It is recommended
that any mineral spirits be first tested for strength and compatibility
with the varnish, by blending them together on a very small scale.
This will minimize loss if the mineral spirits do not work. If
compatible, they will thin the varnish and maintain translucency.
If the solvent is not compatible, the mixture will not
become thinner and may even become thicker and more opaque.
To help avoid the problem of solvent incompatibility, distilled
or rectified white turpentine may be used. Such a grade has been
purified sufficiently for artists' use. Other grades contain residual
materials that may decrease the archival nature of the artwork.
Thinning GOLDEN Polymer
Varnish Distilled water is the preferred
diluent for Golden Polymer Varnish. While tap water may
be used, it may contain impurities such as minerals or bacteria.
Some artists thin water borne materials with alcohol. This practice,
while sometimes very successful, should be approached with caution.
The shorter chain alcohols, like methanol, and ethanol can shock
the varnish and coagulate it, making it cheesy or stringy. This
practice also reintroduces a more hazardous solvent than simply
water. The amount of thinning required will depend upon the method
of application. For spraying, a suitable range is from 1-2 parts
varnish per part diluent. For brushing, a ratio of 3 parts varnish
to 1 part diluent should yield a mixture that flows on well and
allows for leveling and foam release. Satin and matte varnishes
tend to be thicker in the bottle than the gloss varnishes and
may require additional dilution. When thinning, slowly
add the diluent to the varnish while gently stirring.
To ensure an even finish, the varnish must be mixed thoroughly.
Be careful not to create foam bubbles. Do not shake the mixture.
If mixing more than one quart of varnish, a drill with a paint
mixing attachment may be used. Operate it at a low speed and be
careful not to create a vortex which will pull air into the mixture.
If the varnish becomes foamy, let it stand for a half hour or
more to allow the foam to escape, then gently stir. When
working with a Satin or Matte finish, thin down only the amount
of varnish that will be used that day. Storing a diluted
varnish will result in the matting agents settling to the bottom,
where they may become a tightly packed layer. If this occurs,
it may not be possible to fully reconstitute the mixture by stirring.
Applying GOLDEN Varnish
It is preferable to brush
or spray apply Golden varnishes. Other methods, such
as sponging or rolling, are not recommended, as they may result
in problems such as: foaming, loss of film clarity, non-uniform
coverage, excessive film build, sagging, or deposition of materials
from the application tool.
Use a stiff, white hair, chinese
bristle brush with split ends. The split ends and memory of this
type of brush will result in a smooth, even coat of varnish. The
size of the piece to be varnished will determine the size of the
varnish brush. Work from a shallow container to help control brush
loading. The varnish solution should wet only the lower 25-30%
of the length of the bristles. It is always best to apply
the varnish on a horizontal surface in order to minimize running
or sagging. If vertical application can not be avoided,
as with a mural, it is extremely important that the varnish be
thinly applied. In either case, it is better to apply two or three
thin coats with sufficient drying time in between, rather than
one thick coat of varnish. The latter will take longer to cure,
staying soft for some time, and could result in drips or a cloudy
film. Apply the varnish in a manner which allows it to be brushed
out to the most uniform, thinnest film possible. Mentally divide
the work into regions to be covered by each loading of the brush.
These may be based on a systematic grid-like sequence or may follow
natural boundaries of the piece. Maintain an even application
by working from the center of each region outward. Lightly overlap
into still wet, adjacent sections. When applying a satin or matte
varnish, never apply more than two coats. If multiple coats are
desired, start with the gloss varnish to build up and establish
the multiple layers, then finish with one or two coats of the
satin or matte finish. A thick film of these reduced sheen varnishes
will result in film cloudiness, and loss of clarity.
The best way to achieve
an even coating of varnish is to spray apply. This is
particularly true for impasto surfaces. Spray application is required
for any surface where the paint film is fragile, such as gouache,
and should not be touched by application tools. Spraying is also
a useful technique for creating a matte surface. The size of the
surface to be sprayed will determine the best type of spray equipment
to use. These varnishes can be sprayed from an airbrush, airless
or air pressured spray equipment, or refillable aerosol equipment.
In preparation for spraying, make sure all equipment is free of
dirt. Work in an area free of dust and dirt and keep work off
the ground when spraying. Spray three to four light even
coats instead of one or two thicker applications, allowing
enough time for drying between coats (1-4 hours, until surface
is tack free). Release the spray trigger if the motion of the
airbrush is stopped during application in order to avoid an uneven
build of varnish in one spot. Maintain uniform distance
from the surface, and avoid the tendency to use an arcing
motion. Make straight passes across the work, changing direction
once the spray has cleared the edge of the piece being varnished.
Slightly overlap the spray pattern with each pass, until the entire
piece has been covered. To aid in achieving a more even application,
turn the painting 90 degrees in order to apply the subsequent
coat perpendicular to the previous one. A typical spray application
lays down a film only 1/6 to 1/4 the thickness of a brush coat application. If maximum protection is required of the varnish layer,
apply multiple coats. This is especially important when
protecting colorants that are not inherently lightfast, as the
thicker the total varnish film, the greater the protection from
ultraviolet radiation. Because it is not recommended to apply
several coats of a satin or matte finish, underlying layers should
be established using a gloss varnish.
Murals and Architectural Applications
Any paint or topcoat applied to a building, including interior or exterior walls, is considered an architectural coating and subject to regulations limiting the amount of VOC’s (Volatile Organic Compounds) a product may have. Murals painted directly onto these surfaces, therefore, will fall under the same guidelines and all paints, mediums, and varnishes being used will need to comply with the same rules. Containers that are 1 Liter (1.05 Quarts) or less in size, however, are currently exempt from these requirements.
Murals painted directly onto architectural surfaces
- Gallon sizes of our MSA Varnish, Hard MSA Varnish, and Acrylic Glazing Liquid are prohibited in the United States for architectural applications, including interior and exterior murals painted directly onto walls and ceilings.
- Quart containers of our MSA Varnish, Hard MSA Varnish, and Acrylic Glazing Liquid are allowed and can be used. The rate of coverage for these products is approximately 75-150 sq. ft. per quart, depending on the type of substrate and method of application.
- Solvents needed to thin MSA Varnish and Hard MSA Varnish might be limited or prohibited by similar VOC requirements.
- Polymer Varnish is not restricted due to VOC concerns; however, it is only recommended for interior applications.
- Always check local and state VOC regulations as these may include additional restrictions.
Murals painted onto canvas, panel, and other supports
- Currently there are no restrictions for murals completely painted and varnished on an independent support which is then mounted onto an architectural surface.
Call or email Technical Support for additional information or assistance.
Clean all equipment immediately
following application. If tools are wet, Golden Polymer
Varnish can be removed with water. Ammoniated glass cleaner
or a 1:1 solution of household ammonia to water may be use if
the varnish has set. Golden MSA Varnish should be cleaned
from tools with the same solvent used for thinning, followed
by soapy water wash and clear water rinse.
The isolation coat should
cure for 1 day before varnishing. When building up multiple
coats, allow for 3 - 6 hours in between coats. Gently inspect
the surface for tack, which may signify that the coat is not sufficiently
dry. Let varnish cure several days before packing or transporting
art. During transportation and storage, avoid contact of the surface
with packing materials, including glassine, bubble wrap or any
other plastic. NEVER STACK PAINTINGS,
whether varnished or not.
Care and Storage
As Golden Varnishes are
removable, it is important that they not be painted over.
Paint applied over the varnish would also be potentially removable,
and would pose a difficult problem in conservation or restoration
If milkiness or opacity occurs
in varnish layer, then
- if using a satin or matte varnish,
and this only occurs over dark colors, this may simply be the
nature of such a reduced sheen varnish (caused by the presence
of the matting agent). There is no way of applying a satin/matte
finish to a dark color without lightening it (the more matte
the finish, the more potential for lightening dark areas). To
restore the depth of the dark colors, apply a higher gloss to
restore some of the sheen.
- if this is uniform across much
of area, regardless of the darkness of the underlying colors,
it may be caused by moisture entrapment. High humidity or a
damp surface under the varnish layer, often causes loss of clarity.
Using a warm, forced air source to blow across the surface should
help the moisture evaporate, restoring clarity.
- if varnish is not properly thinned,
or is shaken or stirred excessively, air bubbles may become
trapped within the dry film, causing a loss of clarity. The
varnish must be removed.
- if a "frosted" area appears,
a satin or matte varnish may have been applied over an absorbent
surface (this is common for spray applications). The varnish
must be removed, the surface sealed to reduce absorbency (apply
gloss varnish), followed by application of a reduced sheen varnish.
If reflectance is not uniform,
- if surface has varying absorbency,
this may result in uneven gloss. Ideally, such a surface would
first have isolation coat applied to provide a more uniform
surface. However if varnish has already been applied, the surface
must be sealed by applying 1 or more additional coats of gloss
varnish, followed by the desired sheen varnish.
- improper mix of varnish. The
varnish/solvent mixture was not thoroughly mixed. If different
sheens were blended together (gloss with matte), they may not
have been thoroughly mixed. If the diluted varnish is used over
a long period of time without restirring, it may be separating
(matting agents settling). To achieve a uniform finish, start
with a fresh mixture of varnish/solvent (thoroughly stirred)
and apply another coat (may also consider removing the existing
If brush strokes remain, then
- the varnish may not have been
thinned sufficiently to level during application.
- the solvent was not compatible
with the varnish
- if the surface was absorbent,
it may have caused the varnish to dry too quickly, and not allow
it to level.
If the MSA Varnish will not
thin down, then
- solvent is not strong enough
to be compatible. Use a stronger solvent (distilled turpentine,
When spraying, if the surface
is very pebbly or textured, then
- the varnish may have dried before
reaching the surface. This could be caused by
- insufficient thinning (add more
solvent), an extremely dry environment (add humidity, reduce
heat, limit air flow) or by excessive air flow (reduce air pressure).
If the varnish is sinking in
and not developing sufficient gloss, then
- the surface is too absorbent.
Apply additional coats of isolating layers (only if no varnish
is yet applied) or gloss varnish. Excessive dilution of varnish
may also result in this problem.
If the varnished surface is
too glossy, then
- apply a satin or matte finish
of the same kind of varnish already applied.
If the varnished surface is
too matte, then
- apply a gloss or satin finish
of the same kind of varnish already applied.