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Understanding Gamblin Mediums, Solvents & Varnishes

Updated: Aug 10, 2022

Let’s face it: there are a lot of mediums, solvents & varnishes on the market and they all change how paints behave. To find the perfect medium for your work, you just need to understand how they change paint. Read on to see how Gamblin products make it easy.


Painting mediums offer a great deal more than simply extending oil colors. Mediums modify the working properties of oil color from the tube – from a fluid consistency for expressive mark making to a stiff paste for creating thick, crisp marks.

Painting mediums also broaden the visual qualities of our colors – from increasing the transparency of paint layers, to creating a range of surface qualities, from high gloss to matte.

  • Galkyd: Galkyd thins oil colors and increases transparency and gloss. When used in greater proportions with oil color, Galkyd will level brush-strokes, creating an enamel-like surface. Galkyd is our fastest-drying painting medium. Thin layers will be touch-dry in approximately 24 hours.

  • Galkyd Lite: Galkyd Lite thins oil colors and increases transparency and gloss. When used in moderation with oil colors, Galkyd Lite will retain brushstrokes. Galkyd Lite is more fluid and less glossy compared to Galkyd. Thin layers will be touch-dry in 24 to 30 hours.

  • Cold Wax Medium: Cold Wax Medium is made from naturally white, pure beeswax. Formulated to knife consistency, Cold Wax Medium makes oil colors, Gamblin Mediums, and Gamvar thicker and more matte. 

Gamsol is the safest solvent that allows oil painters to utilize all traditional painting techniques without compromise.

Primary Uses of GAMSOL:

  • Thinning oil colors. A little goes a long way; stiff oil colors relax immediately when a little Gamsol is added. Be careful not to thin oil colors too much with solvent alone, this can compromise the ability of the paint to form a paint film.

  • Modifying painting mediums. Our Galkyd line of painting mediums are formulated with Gamsol, so they readily accept Gamsol as a thinning agent. Note: Gamsol should not be added to painting mediums made with natural resins (dammar, copal, mastic). They require strong solvents such as turpentine.

  • Studio clean-up: brushes, palettes, palette knives, etc.

Q: How does Gamsol achieve this level of performance and safety?

A: Most solvents available to artists come from the industrial paint industry where solvent power and cheapness is prized. Gamsol is special: it is made for products and processes that come into more intimate contact with the body such as cosmetics, hand cleaners, and cleaning food service equipment.

Gamsol is a petroleum distillate but all the aromatic solvents have been refined out of it, less than .005% remains.

Aromatic solvents are the most harmful types of petroleum solvents. In addition, Gamsol’s flashpoint allows it to ship via air cargo as a non-hazardous material.

All of these factors have lead to Gamsol being used widely in oil painting classrooms; in those classes, there are no solvent odors, only the wonderful smell of oil colors.

GAMVAR Varnish

Gamvar Varnish saturates colors in your painting and gives your work a unified and protective surface. Developed in collaboration with the National Gallery of Art, Gamvar can be easily and safely removed with Gamsol. Gamvar is virtually odorless and ready to apply. Brush apply using a varnish brush. Do not spray. All Gamvar can be applied when the thickest areas of your painting are thoroughly dry and firm.

  • GAMVAR Gloss: Gamvar Gloss goes on water-clear and stays water-clear. Gamvar Gloss is the original Gamvar formula.

  • GAMVAR Satin: Gamvar Satin saturates colors in your painting, yet dries to a lower gloss level compared to original Gamvar.

  • GAMVAR Matte: Gamvar Matte reduces surface sheen while maintaining the deepest values in your painting.

Sizes & Grounds

A Ground or Gesso is the foundation of an oil painting. The choice we make determines in large part how painting will feel, mark-making possibilities, and how our colors will look when our painting is dry. An acrylic gesso made from synthetic polymer imparts a plasticky texture. An absorbent, thirsty clay board can cause sunken, desaturated color.

A ground with tooth helps grab paint off the brush, meanwhile a smooth surface lends to fine detail linework. Gamblin PVA Size seals the porous fibers of fabric or paper and isolates those fibers from your Gesso, Ground and oil colors. This protects the fibers from acid, making the surface archival. Only fabric and paper supports need sizing. Panel can withstand the acid in oil and may be prepared with just Gamblin Ground. 

Gamblin Ground: Gamblin Oil Painting Ground makes a strong, bright, non-absorbent foundation for oil paintings. Gamblin Ground is formulated from alkyd resin, titanium dioxide, and calcium carbonate – titanium dioxide gives opacity, while calcium carbonate gives tooth for strong adhesion.

Ground Uses: Due to a higher pigment load, Gamblin Ground is thicker than acrylic gesso, and requires less coats and different application techniques. Gamblin Ground may be used to cover an old painting.

This is an economical way to reuse your canvases or panels when the painting doesn’t turn out the way you hoped.

Gamblin Ground may be applied directly over an acrylic primed canvas or panel to provide a bright white surface, reduce absorbency and improve color saturation.

Oil colors may be mixed into Gamblin Ground to create a tinted ground. There are numerous expressions out there about “blank, white canvases”.

Gamblin PVA (Poly Vinyl Acetate) Size: A raw canvas should be sized with Gamblin PVA Size before applying Oil Ground or oil color. Conservation scientists recommend painters use neutral pH PVA size canvas and paper instead of rabbit skin glue. PVA Size provides a stable size layer that seals the canvas but does not swell or shrink like rabbit skin glue goes. This is because PVA size does not re-absorb atmospheric moisture. Gamblin PVA Size is made from PVA that is free of animal byproduct, has a neutral pH, and does not yellow. It also retains its flexibility and does not emit harmful volatiles.

PVA Size on Canvas: Use any style of brush to scrub PVA Size into your canvas. You can apply PVA Size before or after stretching.

A single coat of PVA Size on the front of the canvas is usually sufficient for application. If the canvas has a very open weave showing many pinholes when held up to the light, apply PVA Size to both the front and back.

If you are stretching your canvas before applying PVA Size, ensure that canvas is stretched evenly and tightly. PVA Size will tighten a stretched canvas initially when wet but may relax somewhat once dry.

PVA size will not result in any dramatic difference in the tightness of the canvas like rabbit skin glue.

For very large dimension stretched canvas or when using lightweight linen, apply PVA Size first prior to stretching. Lightweight canvas on larger stretchers can buckle and/or wrinkle on the stretcher frame when dry. Heavier weight canvas has less of a tendency to buckle or loosen. Soap and water can be used to clean brushes after application of PVA Size. PVA Size on Paper: There are papers which are already sized and designed for oil painting. Heavy water media papers like watercolor, mixed-media and some printmaking papers may be used for oil painting once properly treated. Gamblin PVA Size can be used as a sealant for that purpose. The appearance of most papers are changed very little once the PVA Size is completely dry. Only the side of the paper to be painted on with oil colors requires sealing with PVA Size. To limit wrinkling, some papers may require taping down to a rigid panel before applying PVA Size. Allow the sized paper to dry completely before removing the tape. Most paper will require 2 coats of PVA Size. Allow all moisture to evaporate out of freshly sized paper (about 24 hours) before applying Oil Ground and/or Artists Oil Colors.

The above information covers most of the Gamblin Mediums, Varnishes, Solvents & Grounds. Gamblin additionally offers solvent-free mediums as well. We shall cover that in a separate blog post.


Source Credits: Gamblin.


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