Any brief discussion of Painting Techniques will suffer from over generalization. At least, we can offer definitions of the two primary methods of making paintings that artists have been using for hundreds of years. The difference between Indirect and Direct Painting is how artists choose to apply paint.

Indirect Painting

Painters use this method to build up multiple layers of paint and medium to achieve some desired visual effects. Titian, Rembrandt and Rubens are among the great painters who constructed oil paintings with the simple technique of applying three distinct layers:

1. A dark transparent initial layer made from one or a few colors that relate closely to each other, such as the Gamblin Transparent Earth Colors. These colors can be used to block in (draw in) the painting. We recommend contemporary painters use Gamsol odorless mineral spirits and a small amount of Galkyd Lite to thin this layer.
2. A middle layer made from opaque colors, including the lightest values in the painting (Radiant Colors or a tint of Umber, Terra Vert or Portland Greys would be useful for this layer). Consider using Galkyd or Galkyd Lite thinned with approximately 10 - 20% Gamsol.
3. A final glaze layer that modifies the opaque colors and makes the surface very rich. Consider using Galkyd without thinning for an enamel like finish or Galkyd Lite for lighter glazes. An opaque glaze layer is called a "scumble." Because of its transparency, Zinc White is the best white to create this effect. Also, pure hue "highlights" can be added to the top of the painting.

Paintings built in this manner follow the "fat over lean" rule. All painting mediums are considered fat so use Galkyds thinned with Gamsol in the under layers and more painting medium in the upper layers.

For painters concerned about using oil rich colors, consider this visual key: Artists' grade oil paints that look shiny are fat. Artists' grade oil colors that look more matte are lean.

When using tints to build the middle layer, consider the layer lean because all Gamblin Artists' Whites are lean.

This simple system can be organized differently depending on whether painters prefer to build their paintings from dark to light (Leonardo) or light to dark (Rubens). Painters who prefer not to tone the ground will make brighter paintings by applying:

1. Thick opaque under painting as an initial layer
2. Thin transparent glazes to modify that under painting

Painters can also use the Indirect method by applying many glazes of only transparent colors over a drawing or a grisaille. The traditional drawing colors are medium brown (Umber), earth green (Terre Vert) or warm medium grey.

Direct Painting

This method of painting is used to make paintings in a single application. This is an opaque painting technique used by the Impressionists in their early work, the Fauves and the Abstract Expressionists. (But consider a painting made with transparent colors all in one layer a direct painting, too.) Direct painting relies on more planning because artists must consider form and color simultaneously.

A few guidelines:

1. Paint from light to dark
2. Vary brush marks from long stroke to short mark (like Cezanne's) to stippling, etc
3. Scrubbing in multiple directions
4. Scrumbling with a near dry brush

Among the many choices, consider:

• Paint the background to the foreground
• Mix the colors primarily on the palette or on the canvas
• Begin with the middle tones and gradually increase the contrast

For painting wet-into-wet, use mostly artists' grade oil colors with a small of amount Galkyd Slow Dry Painting Medium to increase the fluidity of the paints.

Alla prima is a method of direct painting in a single paint layer usually on a white ground.

Plein Air describes a direct technique of painting a landscape entirely out of doors.

Most painters use a combination of direct and indirect painting. For example, a landscape painting may look better when a glaze is applied to certain areas, such as the sky.

Other techniques

Impasto is the use of thick layers of paint to create texture. Often painters use Galkyd Gel (transparent medium) or Cold Wax Medium (translucent medium) to body oil colors. When painting on linen or canvas, we recommend using ½ Gel and ½ Cold Wax Medium. Using only Galkyd Gel, painters can create impasto of ¼ inch per layer. Using only Cold Wax Medium in a mixture of more than 30% wax (70% oil colors) may cause paintings to crack when moved.

Imprimatura is the application of a wash or glaze of color that tones the canvas before beginning a painting.

Sfregazzi - (Italian: "light rubbing") shadows applied as a glaze over light areas.

Sfamato - (Italian: "softened") making transitions from light to dark very gradual.

Painting with Gamblin Radiant Colors

A hundred years ago painters opened tubes of artists' oil colors purchased at a retail art supply store. Artists' colors had evolved from thin, weakly pigmented fluids into luscious, dense pastes like Gamblin Artists Colors. Painting techniques changed, too. Painters used stiff brushes and palette knifes to created impasto. Glazing was the technique of the establishment and the academy. Independent artists were "loading" paint for form both dark and light areas on canvases by the mid 19th century. And direct painting has dominated 20th painting. So again, times change. Gamblin Artists and painters everywhere are exploring techniques of previous generations of oil painters and trying them out with contemporary materials. Robert Gamblin introduces the Radiant Colors. Eight tints - mixtures of pure color and white,at Value 7 on the Munsell System. Using these Radiant tints, painters can build under paintings in the traditional manner then glazing to achieve optical effects of light and shade.

• Tint = pure color + white (Add white to pure color and make tints.)
• Shade = pure color + black (Add black to pure color and make shade.)
• Tone = pure color + white+ black (Add black to tints and make tone.)

Using tints, painters can make the brightest paintings. Light hits the painting and most of the light bounces directly off the surface. This is a traditional form of direct painting. Using shade, painters can make deep, luminous paintings and use white and tints for accents. Light is captured in the paint layers so the layers glow. Using tone, painters can build paintings by value of pure light tints and grey.

Leonardo Da Vinci used oil paints and "sfumato" technique because he wanted to make paintings that looked real. He made his under painting by adding white (tint) and black (tone) to pure colors. Then, diluting his oil paints, he layered transparent glazes, mixtures of pure color and black - shade, to enhance the sense of depth. Applying purer light colors over the darker glazes, Da Vinci created a warm luminosity in his paintings.

To experiment with Da Vinci's technique: Using the Radiant Colors, create an under painting with Titanium-Zinc White added for brighter (tint + white) colors and Ivory Black for shade (pure color + black). Or use the Radiants and Portland Greys to create impasto then glaze with Gamblin transparent pure colors and Galkyd Painting Mediums. For an enamel like surface, choose Galkyd. For a lighter glaze, choose the low viscosity Galkyd Lite.

J. M. W. Turner's subject is the color of light. His paintings are color arrangements of tints (pure color+white) and tones (pure color+white+black). He preferred painting with no deep colors or rich shades. To Turner's eye, purer colors were the paler colors. Onto a warm-grey toned under layer, Turner applied tints (pure color+white) and still brighter (tint+white) colors. Rather than choose black, he used soft light to deep neutral greys. Tints and brighter colors seem lustrous ... radiant.

To experiment with Turner's technique, try using the Radiant Colors in the light areas. Mix the Radiants with Titanium-Zinc White to make them brighter. Add Portland Grey Light or Portland Grey Medium to tone the Radiants. Mix them with Portland Grey Deep for spare dark accents. Use Galkyd Lite and transparent glazing colors to control the quality of light.

The 19th century Industrial Revolution introduced painters to new mineral colors, manufactured into the high chroma, dense paste like artists' grade oil colors of today. The Impressionists were the first painters able to make bright paintings with little drawing, under painting or glazing. Having abandoned the studio and painters' control of subject and lighting, they explored the natural work looking for the transitory effects of natural light. Monet's technique relied on an arrangement of pure colors, clean tints and white. This direct painting was the perfect technique for landscape painting.

To experiment with Monet's technique, try using the Radiants mixed with Portland Grey Light or Medium. Consider the value of the light. The Radiants are Value 7. Add Titanium-Zinc White to make them brighter. Add a complement (pure color+tint) or Portland Grey Deep to darken the value of the Radiants. Monet often used pure color, such as Prussian Blue, to create shadow.

To make paintings more matte, Robert Gamblin suggests you use approximately 10% by volume Gamblin Cold Wax Medium rather than blot the oil out of the paint. (Artists' grade oil colors require a generous amount of binder to remain flexible.)

Grounds and Varnish

Artists who are concerned with making permanent paintings should consider carefully the quality of all layers of their paintings. They should be as concerned about the layers they do not see (size and ground) as the layers they do see (oil colors, painting mediums and varnish).

Ground

Ground is the foundation of an oil painting.

The first oil paintings were banners -- oil colors painted directly on fabric. Probably painters soon figured out that linseed oil causes fabric to rot. To prevent deterioration, they sized fabric with animal glue. As painters met demand for ever larger paintings, they needed a new lightweight support. Enormous wood panels with multiple layers of gesso cracked and were difficult to move. By using a fabric support, paintings, like banners, could be rolled then stretched and hung in place. Early Venetian oil paintings were painted on fabric prepared with only glue sizing. By adding a white oil ground, painters had a reflective surface that made their colors look brighter.

Oil grounds have been for five centuries a simple mixture of chalk (in Northern Europe) or gypsum (in Italy), white lead and linseed oil. Chalk is a calcium carbonate, which naturally occurs in fossilized shell deposits, like the White Cliffs of Dover. The premium grade of chalk was "champagne" used to make "Paris Chalk." Today we also call calcium carbonate chalk "whiting." Like gypsum, chalk does not make a suitable white pigment because of its poor color and transparency. For making gesso, opacity is not an issue because so many layers are applied. However, an oil ground on fabric should be no more 1/8 inch thick so only a few layers can be applied. By adding a measure of opaque white lead, a thin and bright oil ground can be made.

Gamblin Ground for Oil Painting makes a strong, bright foundation for oil colors. Formulated from alkyd resin, titanium dioxide, and barium sulfate, Gamblin Ground makes canvas and linen stiffer than acrylic "gesso" and more flexible than traditional oil primers. Barium sulfate gives Gamblin Ground its tooth. Titanium dioxide gives Gamblin Ground its opacity.

Because the percentage of pigments is so much higher than in acrylic "gesso," painters need only apply Two Coats of Gamblin Ground instead of the recommended Four coats of acrylic gesso. More coats can be added for smoother painting surfaces. Because alkyd resin is used instead of linseed oil as the binder, Gamblin Ground is more flexible and dries more quickly than lead/linseed oil grounds. Lead/linseed oil grounds must dry for six months and Gamblin Ground is ready for paint application immediately.

Gamblin Ground can be tinted with Gamblin Dry Pigments or Gamblin Artists Colors.

Size

Before a oil painting ground is applied, the canvas is sealed with a size. The size seals the porous fabric and isolates it from the ground and/or oil paints. Linen and cotton will prematurely rot without a size layer. Only fabric supports need sizing. Panels only need to have a ground. Acrylic gesso does not require a size.

PVA Size (poly vinyl acetate glue), diluted with distilled water, is a contemporary size for fabric support. Conservation scientists recommend painters use neutral pH PVA size on linen and canvas instead of rabbit skin glue. PVA provides a good size layer that seals the fabric but does not re absorb atmospheric moisture, swell and shrink like rabbit skin glue does. Painters who want to paint directly on a size, apply one layer of PVA Size to the front and back of the fabric.

We acknowledge and appreciate the research of the Canadian Conservation Institute that helps painters and conservators identify the best PVA to use.

Rabbit Skin Glue is the traditional size for fabric support. Conservation scientists caution painters that rabbit skin glue absorbs atmospheric moisture on damp days and swells; gives off moisture on dry days and shrinks. This movement of the size layer can cause aged oil paintings to crack, according to the Smithsonian Conservation Lab.

Painters can add at least one coat of Gamblin Ground to canvas pre-primed with acrylic gesso to make a better painting surface for oil colors.

Traditional Gesso

Gesso is Italian for gypsum (calcium sulphate dihydrate) which occurs naturally near salt deposits. Calcined gypsum, also called plaster of Paris, when mixed with animal glue, makes a luminous painting surface for fresco and for paintings on wood panels. Medieval painters applied as many as ten layers of gesso on wood panels. By painting alla prima with tempera on gessoed panels they could create "portable" frescoes. Gesso on wood panels makes a good surface for paintings that include burnishing and gilding techniques.

Gesso was not used as a ground for oil painting. The traditional primer for oil painting is an oil ground. Modern "gesso" was formulated by manufacturers of acrylic polymer primer about fifty years ago. Why they decided to call acrylic primer "gesso," a conservator suggested the marketing department wanted to associate new acrylic primer with painting tradition so oil painters would use it. Whatever the reason, the name "gesso" continues to cause confusion.

Gamblin Traditional Gesso makes a traditional absorbent ground for oil paintings on panels. Gamblin Traditional Gesso is a dry mixture of rabbit skin glue, gypsum, marble dust, and titanium dioxide. Robert Gamblin recommends applying four coats Traditional Gesso to both sides of thin or poorly braced panels. Traditional Gesso is too brittle to use with fabric supports.

Varnishing

Varnishing is an aesthetic decision. Robert Gamblin recommends paintings be varnished unless artists truly dislike the look. While waiting 3 - 6 months is best, painters using Gamvar can safely varnish sooner because Gamvar's mild solvent will not dissolve the glaze layers of paintings and paintings today dry quicker. Gamblin Artists' Grade Oil Colors dry more quickly than oil paints of past centuries. (Then linseed oil was usually contaminated with weed seeds that slowed down the drying time of paintings. Contemporary refined linseed oil is pure linseed oil.) Painters can also leave a note on the stretcher bars "ok to varnish in future."

Robert Gamblin formulated GAMVAR (pronounced GAM-MAR), a low molecular weight (LMW) synthetic resin varnish, based on research at the National Gallery of Art. Gamvar has a refractive index similar to damar natural resin varnish. GAMVAR is better because it does not yellow and remains easy to remove. Adding it as the top layer will saturate the colors of paintings and intensify the transparency of glazes.

From painters' point of view Gamvar is an excellent varnish because your paintings will look beautiful today. From conservators' point of view, Gamvar is an excellent varnish because they will be able to clean your painting in 100 years without using such strong solvent that they may harm the paint layers underneath.

Gamvar is not premixed like most varnishes. Conservation scientists have advised Robert to formulate Gamvar as a component system because all varnishes should be mixed and used immediately. Gamvar may be used as a retouch varnish (1 part Gamvar to 5 parts OMS).

Like damar, Gamvar has a high shine. To make Gamvar less shiny, dilute with up to 50% OMS. Also painters can make a matting agent from 2 fl oz of Gamsol OMS and 1 teaspoon of Cold Wax Medium. Dissolve the wax completely in GAMSOL. Add this in place of a percentage of OMS to make Gamvar more matte.

If you prefer a matte varnish, Robert Gamblin recommends you varnish with cold wax medium.

Matte Varnish

Gamblin Cold Wax Medium can also be used as a traditional matte varnish. Apply a thin layer of Cold Wax Medium on to the painting. With a circular motion, apply the Cold Wax paste with a lint free cloth. For large paintings on flexible supports, consider backing the painting before apply Cold Wax Varnish. Wait approximately 24 hours and then buff the painting to the desired sheen. The Gamblin Cold Wax Varnish is easily removed with odorless mineral spirits.

Palettes

Below are links to six palettes that painters will find useful for various painting situations. These palettes can be used "as is", or provide a starting point for the development of custom palettes tailored to specific needs.

High Key Basic Palette	Impressionists' Palette	Transparent Glaze Colors
Landscape Palette	Special Landscape Colors	Old Master Palette