Introduction: The Eternal Gaze of the Painted Face
Portraiture is one of the most enduring genres in the history of painting. To create an oil portrait is to confront the mystery of individual presence, to translate flesh and spirit into color, form, and brushwork. 
Johannes Vermeer, Public domain,
via Wikimedia Commons
The oil portrait, unlike a photograph, is a slow negotiation between the artist and their subject. It involves observation, intuition, calculation, and—in the hands of a master—reverence.
The Renaissance marked a pivotal age when portraiture, particularly in oil, evolved into a genre of profound psychological and technical achievement.
The artists of that era did not merely aim to create a likeness; they sought to immortalize the subject’s dignity, intellect, rank, and soul.
Here we will first explore the technical process of oil portraiture—tools, stages, methods—and then delve into five masterpieces that define the tradition: Mona Lisa by Leonardo da Vinci, Portrait of Baldassare Castiglione by Raphael, Lady with an Ermine by Leonardo, Portrait of a Man in a Red Turban by Jan van Eyck, and La Fornarina by Raphael.
Part I: How to Paint an Oil Portrait – From Canvas to Completion
1. Choosing the Support: The Foundation
An oil portrait begins not with color but with surface. During the Renaissance, artists used wood panels—usually poplar in Italy and oak in Northern Europe. Later, canvas became the preferred support. For a contemporary painter, linen or cotton canvas, tightly stretched and primed with gesso, offers a smooth foundation.
2. Drawing the Subject: Charcoal and Underpainting
The first sketch is typically done with charcoal or graphite. The Renaissance artists like Leonardo da Vinci used silverpoint on specially prepared panels. 
The van Eycks, Petrus Christus,
Public domain, via Wikimedia Commons
Once satisfied with the likeness and proportions, the artist “fixes” the drawing and begins the underpainting—called grisaille when done in monochrome. This phase blocks in values without color, establishing light and shadow.
3. The Imprimatura and First Layers
After the underpainting, artists apply a thin, transparent wash of warm oil pigment over the entire surface—called imprimatura. This unifies the surface tonally and prepares it for the slow build-up of translucent layers. Renaissance artists often used earth tones like burnt umber or raw sienna. The face begins to emerge not with bold color but with whispers of hue and modulated glazes.
4. Modeling Form: Glazing and Scumbling
Glazing involves applying thin, transparent layers of oil paint to create depth and luminosity. Scumbling uses opaque pigment rubbed thinly over dried paint to mute or alter tones. Through these methods, masters like Leonardo could simulate skin’s translucency, the glint in an eye, or the softness of velvet. Oil paint’s slow drying time allows extensive manipulation—edges can be softened, layers reworked, and transitions perfected.
5. Finishing Touches: Detail, Texture, and Varnish
A successful portrait captures not just the anatomical structure but also the spirit of the sitter. Artists refine details like eyelashes, folds of garments, jewelry, and hair highlights. The final step is varnishing, which unifies sheen and protects the painting. Masters used natural resins; modern artists may use synthetic alternatives.
Part II: Renaissance Masterpieces – Anatomy of Genius
Jan van Eyck, Public domain,
via Wikimedia Commons
The technical excellence of the Renaissance painters can be fully appreciated by analyzing key portraits.
This is the Portrait of Margareta van Eyck, The portrait is painted by the Renaissance Artist Jan Van Eyck himself. Look at the gaze of the eyes of the model.
It seems that the model is intensely looking ar the artist making her portrait.
Each offers a unique insight into the evolution of oil technique and the psychological power of portraiture.
1. Leonardo da Vinci – Mona Lisa (1503–1506)
Perhaps the most enigmatic face in art history, Leonardo's Mona Lisa is the consummate example of what oil portraiture can achieve. 
Leonardo Da Vinci, Public domain, via Wikimedia Commons
Lisa Gherardini’s softly modeled face emerges from an atmospheric sfumato—Leonardo’s signature technique of blending without lines.
He used no harsh contours, but a series of feathered glazes that mimicked the way light diffuses on skin. The chiaroscuro—the interplay of light and shadow—models her face into a living presence.
The painting is small in scale but vast in effect. Her gaze follows the viewer, and her smile—subtle, ambiguous—is a triumph of anatomical study and artistic restraint. Leonardo’s understanding of the human skull, musculature, and optics all play into the portrait’s construction. The mysterious landscape behind her, with its winding rivers and broken bridges, is symbolic—a mirror to the complexity of the human mind.
Leonardo reportedly kept the painting with him until his death. It was more than a commission—it was his personal meditation on beauty and existence.
2. Raphael – Portrait of Baldassare Castiglione (c. 1514)
Raphael’s Portrait of Baldassare Castiglione captures the image of the Renaissance courtier, writer, and diplomat with poetic clarity. The half-length portrait shows Castiglione in a fur-trimmed robe and turban-like cap, his gentle eyes and relaxed posture radiating intelligence and humility. 
Raphael, Public domain, via Wikimedia Commons
Raphael paints with soft transitions and restrained color—his palette here is composed largely of greys, browns, and blacks.
What makes this portrait remarkable is its psychological intimacy. Unlike Leonardo’s Mona Lisa, Castiglione engages the viewer directly with a clear and thoughtful gaze.
Raphael’s brushwork is so refined that the strokes seem to disappear, leaving the impression of a living, breathing man.
Technically, Raphael employs underpainting and glazing with mastery. There is no dramatic chiaroscuro, yet the modeling of flesh and cloth is flawless. Raphael was influenced by both Leonardo’s sfumato and Venetian colorism. His approach to oil was polished, methodical, and deeply humanistic.
3. Leonardo da Vinci – Lady with an Ermine (c. 1489–1490)
This portrait of Cecilia Gallerani, a young mistress of Ludovico Sforza, exemplifies Leonardo’s ability to blend portraiture with symbolism. The ermine, held with tender familiarity, symbolizes purity and perhaps alludes to the Duke’s heraldic emblem. 
Leonardo da Vinci, Public domain,
via Wikimedia Commons
Leonardo here experiments with bodily movement—Cecilia is turned to her right, her gaze following some unseen stimulus, suggesting alertness and thought.
The portrait is painted on walnut panel, a typical Italian support. Leonardo uses sfumato and glazing with consummate skill, creating skin tones that glow softly, with subtle modulations across cheekbones and hands.
Her eyes glisten with life, and each strand of hair is painted with exquisite precision.
Beyond technical brilliance, the painting represents a shift in Renaissance portraiture: the subject is not static but dynamic, emotionally and physically engaged.
4. Jan van Eyck – Portrait of a Man in a Red Turban (1433)
Often considered a self-portrait, this work is one of the earliest examples of Flemish oil technique at its height. Van Eyck’s use of oil—superior to tempera for its flexibility—transformed Northern painting. 
Jan van Eyck, Public domain,
via Wikimedia Commons
Here, he applies countless layers of translucent glaze, creating an almost photographic precision.
The sitter's face, lit from the front, is rendered with astonishing realism. You can detect stubble, veins, pores. His turban—a complex twist of crimson fabric—catches the light with minute gradations.
Unlike the smoother Italian sfumato, Van Eyck celebrates detail, precision, and surface texture.
The inscription “Als ich kan” (As I can) on the frame implies personal authorship. This portrait does not seek ideal beauty; it asserts technical prowess and individual presence. Van Eyck’s innovations paved the way for the full flowering of Northern Renaissance portraiture.
5. Raphael – La Fornarina (c. 1518–1519)
Painted in the final years of Raphael’s short life, La Fornarina is believed to be a portrait of his lover, Margherita Luti, the daughter of a Roman baker. More sensual than his earlier works, the painting captures a nude woman with her hand modestly placed across her chest, her gaze demure yet knowing.
Technically, it is a triumph of oil technique. The flesh is painted with warm, transparent glazes that reveal a softness rarely matched in art. Her arm is adorned with a bracelet inscribed “Raphael Urbinas”—a signature of possession and affection. Behind her, a myrtle bush (symbol of Venus) reinforces the theme of love and desire.
The painting blurs the line between portrait and allegory. While it clearly depicts a real woman, the idealization and symbolic elements elevate it to a mythic level. Raphael’s control of oil is absolute—each tone, highlight, and contour feels inevitable.
