Throughout the years of consulting with oil painters and answering
their technical questions, the subject of painting mediums has
dominated our interactions. Understanding painting mediums can seem
like a lifelong pursuit. This article aims to take some of the guess
work out of choosing the right painting medium by focusing on your own
artistic intentions.
Oil painting mediums are simple. Mediums make oil colors thinner,
thicker, glossy, or matte. Mediums can either speed up or slow down the
drying time of oil colors. These are the working properties that Robert
Gamblin focused on when he developed the array of Gamblin alkyd painting
mediums. By focusing on working properties rather than ingredients, we
can liberate painters from their reliance on toxic turpentine and old
concoctions that make paintings darken and crack as they age. In
consulting with painters who want to give up mediums that contain
strong solvents, we ask “what does your medium do?” rather than “what
is in it?”
All painting mediums can be placed into two groups: fluids and gels.
Fluid mediums can be split into two categories: low viscosity and high
viscosity. “Viscosity” refers to a material’s resistance to movement.
Low- viscosity materials are very fluid, like water, whereas high-
viscosity materials are thicker, like molasses. These two groups of
fluid mediums have very different effects on paint layers.
Low-viscosity fluid mediums are great for creating thin washes of
color, especially for underpainting techniques. When a moderate amount
of low-viscosity fluid medium is added to oil colors, they retain the
brush marks as the paint layers dry. The slowest-drying versions of
low-viscosity mediums are simple mixtures of one part linseed or poppy
oil mixed with an equal amount of Gamsol OMS. Gamblin Galkyd Slow Dry
will allow painters to work wet into wet for approximately 24 hours.
Galkyd Lite is a fast-drying, low-viscosity medium.

High-viscosity fluid mediums create self-leveling effects, giving
the oil colors an enamel-like quality. A mixture of one part Stand Oil
and one part Gamsol OMS would create a slow-drying, high-viscosity
medium. Gamblin Galkyd is a fast-drying, high-viscosity painting
medium. Galkyd is excellent for glazing techniques, as thin layers dry
within 18 hours. TIP: Galkyd is the fastest-drying Gamblin medium. As
an economic concern, consider adding a small amount of Gamsol to the
Galkyd periodically to prevent the medium from drying in the bottle.
To view a video demonstration on Gamblin fluid painting mediums, please visit: http://www.youtube.com/GamblinArtist
Gel painting mediums extend oil colors without making them fluid.
They are useful in painting techniques where defined brushwork is
desired. Neo Megilp is a soft gel medium which imparts a silky
smoothness to the oil color. As a glazing medium, Neo Megilp adds
“body,” which means your glaze will be thicker. You can add a thin
layer to your canvas and then paint color into the medium. This was
Turner’s technique for creating atmospheric glazes. Neo Megilp is
moderate to slow in its dry time as compared to the other Gamblin
mediums.
If Neo Megilp is a soft, slower-drying gel, Galkyd G-Gel is a
stiffer, faster-drying gel medium. G-Gel is formulated for painters who
want to create transparent impasto layers that hold brush marks. G-Gel
makes impasto of approximately 1/4" thick.

To varying degrees, all of the Gamblin painting mediums mentioned
thus far will increase the gloss level of oil colors. This gloss level
can be modified through the use of our Cold Wax Medium. Made from a
simple mixture of naturally white beeswax and Gamsol, Cold Wax Medium
can be used straight to make oil colors thicker and more matte. It can
also be used to lower the sheen of any of our other painting mediums.
TIP: mix the Cold Wax Medium with Gamsol into a fluid consistency
before adding to the fluid painting mediums.
Whereas all of the Gamblin alkyd-based painting mediums increase the
flexibility of the paint layer, the Cold Wax Medium will make paint
films more brittle. For this reason, we recommend to painters using
more than 30% Cold Wax to their oil colors to paint on rigid painting
supports, rather than stretched fabric. Or Cold Wax Medium can be made
more flexible by mixing it with an equal part G-Gel.
To view a video demonstration on Gamblin gel painting mediums, please visit: http://www.youtube.com/GamblinArtist
Drying rate is another important consideration when choosing
painting mediums. The drying rate of a medium will greatly influence
other working properties. Fast-drying mediums may feel too “sticky”
under the brush, and the artist will be compelled to slow its drying
rate. Gamblin alkyd-based painting mediums are perfectly compatible
with natural drying oils, such as refined linseed, poppy oil, and Stand
Oil. When these oils are added to alkyd mediums in moderation, they
efficiently slow down the overall drying rate.
This focus on working properties can guide painters to the medium
that “feels right” underneath the brush or the palette knife. Consider
your own artistic intentions when choosing the right medium for your
own work. If a painting medium straight from the bottle is not quite
right, keep in mind that all of these mediums are completely compatible
with each other.
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