Saint Francis Borgia Helping a Dying Impenitent

Sketch the figures of Saint Francis Borgia and the dying impenitent using charcoal or thinned paint.

Tip — Ensure the composition has a clear focal point and avoids dividing the canvas in half.

Initial Sketch

Mix black, ultramarine, and white with oil of copavia (or a modern equivalent like dammar varnish/solvent mix). Paint the entire scene in monochrome (grisaille), focusing on value and form.

Tip — Mentally exclude red and yellow hues to focus on the structural light and shadow.

Grisaille Underpainting

Begin glazing and scumbling with oil. Apply transparent coats of red and yellow tones over the grisaille, similar to tinting an engraving with watercolors.

Tip — Glazing is a transparent coat of color; it allows the underlying grisaille to show through, creating depth.

Glazing

Allow the grisaille layer to dry completely. This may take days to weeks depending on thickness and environment.

Tip — Oil paint dries by oxidation, not evaporation; do not rush this step.

Oxidation Drying

Use scumbling (semi-opaque painting) to adjust tones, particularly over darker grounds where it may create a 'grey bloom' or coldness if not managed carefully.

Tip — Scumbling allows the underlying painting to make itself felt; use it to soften transitions or add texture.

Scumbling

Apply subsequent layers ensuring each contains more oil than the previous ('fat over lean') to prevent cracking.

Tip — If a layer contains less oil, the final painting will crack and peel.

Fat Over Lean

Once fully dry, apply a final varnish if desired, though the initial glazes may have used varnish/oil mixes.

Tip — Ensure the painting is completely dry to the touch (usually within two weeks, but longer for thick layers).

Final Varnish