Modifying Acrylic Paints
Each project demands using paints
that meet all the requirements to insure a long life. Textile
work needs a paint system that will remain soft and flexible so
it wont crack when worn and laundered. Harder, less pliable
paints have better adhesion and resist peeling for non-porous,
rigid supports such as metal. Before beginning a project, it is
critical to understand factors that will effect the artwork after
it leaves the artist studio.
Most of the GOLDEN paint lines have very similar
acrylic resins. They are flexible, but not so soft that it remain
tacky when dry. This is ideal for artwork applications on canvas
and some textile work, but they need to be modified for more demanding
applications on other supports.
Making Acrylics Harder
GOLDEN Airbrush Transparent Extender
(see GOLDEN Airbrush Transparent Extender Information Sheet
for mixing instructions) is essentially a "colorless"
airbrush color that can be mixed with or sprayed over the Fluid
Acrylics as a top coat. The hard acrylic resins in the Extender
resist pull-up when masking is peeled off of its surface. GOLDEN
Airbrush Colors have the same hard acrylic polymer. This is
one of the reasons they work well with "loose" masks
or low-adhesive masking films.
GOLDEN Airbrush Medium is
used to blend into the acrylic paints to make them sprayable.
Also having hard resins, it is designed to most effectively work
with the Fluid Acrylics at a 1:1 ratio. Thicker paints will require
more Airbrush Medium. Refer to the GOLDEN Airbrush Medium Information
Sheet for suggested starting ratios with other paint lines.
Generally speaking, the majority
of an airbrushers needs can be met with GOLDEN Airbrush
Colors and/or the Fluid Acrylics (modified with Airbrush Extender
Thinning Acrylics Properly for
Artist Colors produces several lines of
acrylic paints that can be modified to be sprayed. GOLDEN Heavy
Body Acrylics, Fluids Acrylics, Iridescent/Interference Colors,
High Load Acrylics and Matte Acrylics can be adjusted
for spraying. Only Airbrush Colors are ready to spray.
Rather than an inconvenience, mixing paints offers absolute control
of the paints. The key is to know the pros and cons of each paint
line and medium. Refer to the GOLDEN Products for Airbrushing
Chart (Figure 1) for a quick reference of which product
line(s) is suited for a particular use.
GOLDEN Paint Lines
Air Pressure (P.S.I.)
Illustration (hot- press
20 - 40
Fine Art (canvas, sign board,
Colors, Fluids, High Loads, Heavy Bodies
Medium or Transparent Extender
25 - 50
Automotive (helmets, gas tanks)
25 - 50
Textile (tee-shirts, leather,
40 - 70
Utilizing All Tools
The professional artist
typically employs several application methods to create an artwork.
While there are many "freehand" airbrushers that only
use only an airbrush (without any other tools or masking), the
majority of airbrushers use all available tools and methods to
render an artwork. The preliminary sketching is just as important
in airbrushing as it is in other painting techniques. Proper masking
techniques are also a necessity.
Perhaps the most misunderstood
concept about using an airbrush is when to lay the airbrush down
and use the other tools and techniques to compliment the sprayed
areas. Commercial illustrators will use subtractive techniques
and utilize the whiteness of their illustration board. Scratching,
erasing, and ammonia-based cleaning products are used to remove
certain areas of paint.
The effectiveness of hand-painting
should also not be disregarded when airbrushing. It is much easier
to detail with a paint brush than with an airbrush. When used
together, they will increase the overall realism.
An important step in
preparing for airbrushing involves making sure that the paints
are properly mixed. GOLDEN Acrylics are made with lightfast pigments.
When these dense particles are put in a thin medium, they have
a tendency to settle to the bottom of the container. This "soft
settling" is the result of phase separation. Phase separation
means that the materials in the paint physically separate: the
most dense (heaviest) materials go to the bottom, and the rest
form layers on top. In color blends, denser pigments like Titanium
White commonly form the bottom layer.
GOLDEN Artist Colors puts a ceramic
mixing ball (technically known as a "barundum") in every
bottle of Airbrush Color. Paint can be mixed easily by simply
shaking the container. Begin each day of painting by shaking all
of the bottles of Airbrush Colors intended for use that day. This
vigorous mixing will make the paints quite homogeneous. Pre-mixing
well in advance of spraying allows time for air bubbles to dissipate.
Bubbles can affect how well the paint will spray. Sticking to
this daily ritual will assure that the paints never are allowed
to develop the phase separation, which means less shaking in the
To mix paints that need to be thinned
with medium, reuse old Airbrush Colors containers or add a mixing
ball to a new container. Try to do the majority of mixing before
spraying. This is important when storing blends, as many pigments
will "crash" harder than the pigments used in the Airbrush
Colors. "Crashing" refers to a hard settling of pigment
that is difficult (and sometimes impossible) to re-stir into suspension.
Be sure to mix even the pre-made Airbrush Colors thoroughly. This
leads to a more consistent color, less clogging, and better film
formation. Many spraying problems can be attributed to improper
mixing and thinning.
Thinning with GOLDEN Mediums
Ideally, the Fluids should
be thinned with GOLDEN Airbrush Medium to reach the proper viscosity
for spraying. Airbrush Medium is a blend of acrylic polymers,
retarders, levelers, and flow enhancers. When blended with an
acrylic paint, it produces paints with excellent spray characteristics
(refer to the GOLDEN Information Sheet on Airbrush Medium for
addition amounts and other information). There is a limit to how
much Airbrush Medium should be added to a paint, mainly because
too much retarder can result in color pull-up when masking.
If additions of GOLDEN Airbrush
Medium begin to exceed 2 parts medium to 1 part paint, then the
artist should consider either adding GOLDEN Airbrush Transparent
Extender for further thinning, or for more dramatic thinning,
add water. By mixing 2-10 parts of Extender to 1 part Fluid Acrylic,
the palette of the airbrush artist is increased to over 40 colors.
Similarly, the GOLDEN Iridescent & Interference Colors, High
Load Acrylics, and Heavy Body Acrylics can be reduced to be spray-applied.
These mixture should be used within a week or so, as many of the
pigments may crash hard or cause slow thickening over time.
Thinning Paints with Water
Water can be added for
minor viscosity adjustments. For example, if GOLDEN Opaque Airbrush
Color Napthol Red Light seems to be slightly thick for a particular
application, a 10-15% addition of water will bring it closer to
the required viscosity range. Water additions of this level should
not result in a weak film or alter spray performance.
GOLDEN Fluids (400-700 cPs) are
typically too thick to spray, and need to be thinned to a more
proper viscosity range. They could be thinned with water alone,
but doing so first produces a paint that can quickly clog an airbrush,
and eventually a weak film. It would also have a high tendency
to sag or run, as there would be a very low level of many important
paint additives. The better approach is to add a medium instead
Adjusting GOLDEN Airbrush Colors
Just because GOLDEN Opaque
and Transparent Airbrush Colors are ready-to-spray does not mean
that they cannot be adjusted for individual needs. Opaque Airbrush
Colors have an incredible amount of pigment, as do most GOLDEN
paint lines. With intense colors like Dioxazine Purple or one
of the Phthalo colors, adding GOLDEN Airbrush Transparent Extender
will bring out the brilliancy of the pigment.
Transparent Colors, approximately
1/10th of the strength of the Opaque Line, may also be adjusted.
Adding the Extender will increase transparency of a color, while
adding Opaque Colors will intensify them. Additions of Transparent
Extender also make the paint physically stronger. Because of the
high level of pigment in the Opaque Colors, there are times when
a thin film may lift when masking is burnished over them. Adding
10 - 20% GOLDEN Transparent Extender should alleviate the problem
without significantly decreasing the pigment level.
Adjusting Air Pressure for Each
Many airbrushers get
comfortable with one air pressure and don't adjust for each application.
"Atomization" can be altered from a stipple pattern
to an extremely fine spray. GOLDEN Airbrush Colors can be sprayed
as low as 5-7 p.s.i. for a stipple pattern, and up to 60 p.s.i.
for absolute atomization. Of course, adjusting the air pressure
also affects other attributes. Low pressures produce thicker paint
films that take longer to dry before friskiting1,
and can increase the chance of paint drying in the nozzle and
on the needle. High pressures can inadvertently lift masks, cause
overspray, and can result in an uneven film that may feel "powdery"
or rough, which may lessen masking adhesion.
Paint Viscosity in Relation
Paints made specifically
for airbrush illustration usually have a viscosity (relative thickness)
of 35-60 Centipoise. Viscosity is the measurement of resistance
of a medium using a Viscometer. The unit of measure is a Centipoise,
or cPs. 1 cPs is the resistance of water, so 40 cPs is forty times
the resistance (or viscosity) of water. 35-60 cPs is ideal for
excellent atomization in an airbrush with a .18mm nozzle size.
Thinner paints act similar to water, causing runs and also have
a tendency to "spiderweb" outward. If a thinner paint
is used, adjust the air pressure accordingly. Similarly, thicker
paints, such as pre-made fabric paints, or GOLDEN Fluid Acrylics
would have to be sprayed at a much higher pressure. Fabric paints
are commonly intended to be used in an airbrush with a nozzle
of .25mm or larger.
GENERAL AIRBRUSHING NOTES
Filling the Color
as this may seem, many artists have had spills ruin their artwork
simply because the color cup was too full. Overfilling often results
in wasted paint, so it is always better to put less than what
is expected to be used into the color cup. If spilling is a recurring
problem, consider an airbrush with a covered cup, or a larger
capacity airbrush and/or cup.
The following suggestions
are generally meant for even gradations of color. These application
techniques can take many hours of practice to achieve satisfactory
results. Learning the right way to spray does not come from reading,
but experience. However, these main points should minimize the
- Build up paint films very slowly.
- Avoid heavy "wet"
films which take long periods of time to fully dry.
- If a film is wet, use the airbrush
(air only) to speed drying.
- Add Airbrush Extender if the
paint seems to always be too strong, especially colors like
- Always spray with the airbrush
as perpendicular to the surface as possible. Spraying at an
angle will result in over-spray.
- Move the elbow, not the wrist,
to keep the spray consistent.
- Start spraying before a masked
area, and continue past it to avoid paint buildup at either
Masking off areas can
produce hard distinct edges when done properly. Learn the general
rules of masking techniques on test pieces before using them on
an actual artwork.
- Before laying Friskit down,
wipe the surface with a soft cotton cloth. This will remove
eraser dirt, excess graphite, and body oils (fingerprints).
- Proper drying is essential to
avoid color pull-up (see next section).
- Select the proper masking for
each substrate. Masking tape can damage illustration board.
- Dont excessively rub the
masking in order to get good adhesion. If they arent sticking
to the paint surface, lightly spray a coat of Airbrush Transparent
Extender over the film, allow to dry, and continue.
- Weaker airbrush films may lift
when water-based masking fluids are applied over them. Spray
a light layer of Airbrush Transparent Extender over very thin
films and let cure before using such masks.
- If a paint film is grainy, masking
may not adhere well. Apply a thin coating of Airbrush Transparent
Extender over it, or mix Extender into the paint to even the
ACCELERATED DRYING TECHNIQUES
Proper drying of a film is
critical when employing friskit techniques to an illustration.
If the film is not fully dry, paint can lift off of the board
as the mask is pulled up. Use tools like hair dryers, fans and
heat lamps to speed drying, all of which should be used with caution.
Airflow can lift pieces of Friskit. Heat sources can warp illustration
board and wrinkle the Friskit. Additionally, the heat can increase
the adhesion of the mask to the board. In extreme cases, this
can cause paint pull-up, even if completely dry.
are some of the techniques used to increase productivity by lessening
the amount of drying time. For more information about the drying
process of acrylic paints, (refer to the GOLDEN Information Sheet
"Technical Notes on Drying").
a drying area in the studio for speeding the curing time of
paint films. Adjustable desk lamps with heat bulbs or high wattage
bulbs can create a higher temperature/lower humidity environment,
that will allow the paints to be nearly cured in the time it
takes to flush out an airbrush (see figure 2).
drying of paint films with hair dryers & heat lamps.
wary of excessive heat. Friskit can soften and cause pull-up,
or be wrinkled. Illustration board can be warped.
forming in the Friskit are an indication too much heat is being
applied. Allow it to cool off before continuing.
using heat to cure an artwork, allow it to cool before applying
masking over it to avoid inadvertent adhesion from the heat.
is essential for faster drying.
a small fan alongside a wall to improve circulation. It is not
necessary to point a fan directly towards the drying area, especially
when using a hair dryer as well (See figure 3).
1Friskit® - a low adhesive
clear masking used primarily in commercial illustration.
The above information is based on research and testing done
by Golden Artist Colors, Inc., and is provided as a basis
for understanding the potential uses of the products mentioned.
Due to the numerous variables in methods, materials and conditions
of producing art, Golden Artist Colors, Inc. cannot be sure
the product will be right for you. Therefore, we urge product
users to test each application to ensure all individual project
requirements are met. While we believe the above information
is accurate, WE MAKE NO EXPRESS OR IMPLIED WARRANTIES OF MERCHANTABILITY
OR FITNESS FOR A PARTICULAR PURPOSE, and we shall in no event
be liable for any damages (indirect, consequential, or otherwise)
that may occur as a result of a product application.