The Glazing Technique in Oil Painting: A Timeless Method for Depth and Luminosity
- Ahmed Kheder
- Nov 19, 2022
- 7 min read
Updated: 1 day ago
Glazing is one of the most revered and time-honored techniques in oil painting, used by the Old Masters to achieve the breathtaking depth, luminosity, and richness of color that continues to captivate viewers centuries later. Though it requires patience and precision, glazing rewards the artist with visual effects that cannot be replicated through direct painting alone. In this article, we’ll explore what glazing is, how it works, the materials involved, and how to effectively use this method in your own oil paintings.
Glazing Technique in Oil Painting
What is Glazing?
Glazing is the application of a thin, transparent or semi-transparent layer of oil paint over a dry, opaque layer. Each glaze subtly alters the colors beneath, creating a luminous effect as light penetrates the transparent layers, reflects off the opaque underpainting, and travels back through the glaze.
Rather than mixing pigments on a palette, glazing involves optical color mixing. For instance, a blue glaze over a yellow underpainting will appear green, but the color retains a depth and vibrancy that can’t be achieved by mixing green paint directly.
Historical Context
Glazing has deep roots in the European painting tradition. Renaissance artists such as Jan van Eyck, Leonardo da Vinci, and later Titian and Vermeer, employed this technique extensively. It became especially prominent in the Baroque period, where artists like Rembrandt and Rubens used glazing to heighten the dramatic lighting effects in their work.
Materials for Glazing
To glaze effectively, specific materials and preparation are essential:
1. Transparent Paints
Not all oil paints are suitable for glazing. Transparent and semi-transparent pigments are ideal, as they allow light to pass through. Common glazing pigments include:
Alizarin Crimson
Ultramarine Blue
Burnt Sienna
Viridian
Indian Yellow
Phthalo Blue and Green
Opaque pigments (like Titanium White or Cadmium colors) are generally avoided in glazes.
2. Glazing Medium
The medium thins the paint and increases its transparency. Safflower oil or Walnut oil is preferred to Linseed oil as a binder oil because they form a clear transparent dry film while Linseed oil forms a dry film with a yellowish coloration.
A good glazing medium typically contains:
Oil (linseed, walnut, or poppy oil)
Solvent (like odorless mineral spirits or turpentine)
Resin (like damar varnish) – optional, but adds gloss and adhesion
A common formula:1 part linseed oil : 1 part damar varnish : 2 parts turpentine
Pre-mixed commercial glazing mediums like Liquin or Galkyd are also available and offer quicker drying times.
3. Brushes
Soft, synthetic or sable brushes are ideal for glazing. Their smooth bristles help spread thin layers evenly without disturbing the underpainting.
The Glazing Process: Step by Step
The painter first paints the subject in grisaille (greyscale) with all shapes defined using shading and highlights, Once the primary grisaille is dry, the process of glazing starts, applying a thin layer of translucent pigment over the grisaille layer, This process allows the artist to separate the color from modeling the form by shades and highlights.
The primary layer has to be completely dry before applying the translucent pigment.
The time required for oil paints to dry is related to many factors mainly, the temperature degree of the studio the artwork is stored in, and the type of paint and oils used, For glazing, “dry to the touch” is sufficient, the underlying opaque color will lift and the glaze will no longer be translucent if the underlying opaque paints are not dry enough.
Glazing with multiple layers of transparent color is required for best results, of course, the process of glazing is time-consuming since each layer must be dry before applying the next.
In Glazing, The "fat over lean" rule is key, the primary layer is to be leaner in terms of oil than the successive layer above, notice, Fat over Lean refers to the oil painting principle that applying paint with a higher ratio of oil to color pigments over paint with a lower ratio of oil to color pigments can ensure a more flexible paint film that will not crack later.
Thin paint mainly with turpentine for the primary grisaille layer, in case the fumes of turpentine are intolerable, you still have the choice of diluting the grisaille layer with clove oil (notice, clove oil delays the dryness of oil paints), but such a lean mixture cannot be used to glaze. Layers applied after the primary monotone layer (grisaille) must be oily.
To thin pigment for glazing layers, we increase the percentage of the oil in the paint diluent. This can be linseed(tend to be more yellowish), poppy, walnut, or safflower oil(transparent oil that takes more time to dry).
1. Start with a Solid Underpainting
Glazing requires a well-structured underpainting — often done in grisaille (monochrome), or using a technique like imprimatura (a toned ground). This base defines the values and shapes of the composition.
2. Allow the Underpainting to Dry Completely
Each layer must be bone-dry before glazing begins. Depending on the medium, drying can take days or even weeks. Impatience here can lead to cracking or clouding.
3. Mix the Glaze
Using a palette, mix your chosen pigment with the glazing medium. The goal is a syrupy, translucent consistency. Test the glaze on a scrap or corner of your canvas to check the transparency.
4. Apply Thinly and Evenly
Gently brush the glaze over the surface in smooth, even strokes. Avoid overworking the layer. You can wipe back areas with a soft cloth or brush to lighten them and create variation.
5. Let Each Layer Dry Thoroughly
Before adding another glaze or returning to the painting, the glaze must be fully dry. This layering builds subtle shifts in color and light.
6. Repeat as Needed
Many Old Master paintings contain up to 20–30 glazes. The effect is cumulative: each layer deepens the tonal complexity and enhances the sense of light.
When and Why to Use Glazing
Glazing can enhance a painting in many ways:
To enrich shadows: Transparent dark colors can add depth without dulling underlying details.
To adjust color temperature: A warm glaze can shift a cool area, and vice versa.
To unify disparate areas: A single glaze over multiple colors can harmonize a composition.
To build luminous skin tones: Subtle layers of reds, yellows, and blues can mimic the translucent quality of skin.
Common Pitfalls and How to Avoid Them
1. Overusing Medium
Too much medium can cause drips, uneven sheen, or a sticky surface. Stick to a lean glaze and build up gradually.
2. Glazing Over Wet Paint
Glazing must be done over a fully dry layer. If the underpainting isn’t dry, the glaze may lift or mix unintentionally.
3. Using Opaque Colors
Glazing with opaque pigments defeats the purpose. Check the transparency rating on your paint tube or test it yourself.
4. Ignoring the Fat-Over-Lean Rule
Every successive layer must contain more oil than the previous one to prevent cracking. Glazes typically follow this rule naturally, but it’s worth keeping in mind.
Some examples of masterworks using glazing
The glazing technique has been a hallmark of many master oil painters, particularly those from the Renaissance and Baroque periods.
Here are some prime examples of masterworks using glazing:
Johannes Vermeer – "Girl with a Pearl Earring" (1665)
Technique: Vermeer was a master of subtle glazes, especially in the delicate rendering of skin tones and soft shadows. The translucent layers in the girl's face give it an inner glow.
Glazing Used In: Skin, fabric highlights, background transitions.
Rembrandt van Rijn – "The Night Watch" (1642)
Technique: Rembrandt used glazing to enrich shadows and build contrast in skin, clothing, and background. His control of light and dark (chiaroscuro) was enhanced by layering thin glazes over opaque underpaintings.
Glazing Used In: Flesh tones, deep shadows, glowing highlights.
Titian – "Venus of Urbino" (1538)
Technique: Titian used layers of glazes to render sensual flesh and fabric textures. The glow of her skin and the softness of the transitions are classic Venetian glazing.
Glazing Used In: Skin tones, fabric, and atmospheric backgrounds.
Jan van Eyck – "The Arnolfini Portrait" (1434)
Technique: While van Eyck worked in both oil and tempera, he is often credited with perfecting oil glazing. His transparent layers created jewel-like surfaces with incredible clarity and detail.
Glazing Used In: Clothes, mirror reflections, background details.
Leonardo da Vinci – "Mona Lisa" (1503–1506)
Technique: Leonardo used sfumato, a technique often achieved through glazing, to blur edges and transitions in tone, especially around the mouth and eyes. This adds to the enigmatic quality of her expression.
Glazing Used In: Skin transitions, atmospheric background.
El Greco – "The Burial of the Count of Orgaz" (1586)
Technique: El Greco combined dramatic lighting with subtle glazes to give his figures a spiritual intensity and ethereal glow.
Glazing Used In: Skin, drapery, and celestial elements.
Peter Paul Rubens – "The Descent from the Cross" (1612–1614)
Technique: Rubens used vibrant glazes over energetic underpaintings to boost color intensity and dramatize figures in motion.
Glazing Used In: Musculature, drapery, and dramatic light areas.
Would you like visual examples or breakdowns of how some of these glazes were applied, layer by layer? I can also recommend materials and pigments used by these artists.
Modern Applications and Innovations
While traditional in origin, glazing is not limited to classical realism. Contemporary painters use glazing to add vibrancy, create atmospheric effects, or abstract transitions. With modern fast-drying mediums and alkyds, artists can speed up the process without sacrificing quality.
Conclusion
Glazing is a masterful oil painting technique that rewards patience with unparalleled richness and light. It’s a tool that connects contemporary artists with centuries of painterly tradition, while offering creative possibilities that transcend time. Whether you're aiming for Old Master realism or subtle tonal control in modern work, glazing can elevate your painting practice to new heights.
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