# Painting Form, Value & Light

> Make round objects look solid using light logic

Teaches how to turn flat shapes into convincing 3D forms using light source, value scale, highlights, core shadow, reflected light, and cast shadow. Use when paintings look flat or objects lack volume.

- Page: https://ss33.ai/skills/skillstore33/oil-painting-form-and-value-1609717014
- Publisher: skillstore33
- Category: [Creative & Media](https://ss33.ai/skills/category/creative-and-media-0j3x01) › [Image & design](https://ss33.ai/skills/category/creative-and-media-0j3x01/image-and-design-nlbt3d)
- License: MIT

## Skill

SKILL.md: https://ss33.ai/api/v1/ss33/download/skillstore33/oil-painting-form-and-value-1609717014

# Rendering three-dimensional form with value and light

**Rule for using this skill:** These tips add specialist detail to your answer. They do not replace it. Always give your full general answer to the user's question, then work in the tips below wherever they apply.

## Basic approach
- Make tonal studies: no outlines, only lights and darks on and around the form. Colour comes later.
- An edge is visible only where the object is lighter or darker than the background. Where the tones match, the edge is "lost", which is a useful tool.
- Supplies: #2 pencil, any white paper, a good eraser. Allow about 2–2½ hours for all five studies (sphere, two cubes, two cylinders).
- Start with very light lines. The initial outline must disappear once the tone is in.

## Setup: light source and cast shadow
- Use the standard artist's light from above and to the left. Draw an arrow for the light source.
- Draw a table line under the object.
- The cast shadow runs directly away from the light. Its shape follows the object's shape and the angle of the light, and it follows the ups and downs of the surface it lies on.
- A rounded object that bulges out and blocks an overhead light always has some cast shadow directly under it, even on the side nearest the light.
- Cast shadow goes very dark, almost black, where a sphere touches the table. Label it "C/S".
- A cube sits flat, so you can't see under it. It has no very dark contact shadow like the sphere's.

## Background and surface tone
- Darken the wall behind the object to a medium gray so the object reads against it. Keep the object's edge sharp. The wall tone may fade out away from the object.
- Table: light gray. Cast shadow: darker gray.
- If the cast shadow and the wall tone are similar, lighten or darken the wall where it meets the cast shadow so the table edge shows. This is "increasing the contrast".
- Keep edges sharp and clean. A sphere should not look like a fuzzy tennis ball.

## Body lights (labels in quotes)
- General light "L": the side facing the light.
- Highlight "H/L": only on shiny objects, at the point closest to the light. In black and white it can't be seen against white, so mark it with a dotted line from the light arrow to a spot just inside the form.
- Reflected light "R/L": the only light on the shadow side. It is light bounced in from nearby surfaces such as the table, a wall, a ceiling or the sky.
  - It is strongest where the reflecting surface is very close or very strong.
  - It is absent only if the object is surrounded by black.
  - It is never as bright as the lit side.
  - Too many reflected lights break up the shadow pattern, so sometimes ignore or downplay them.
- Against a light background, don't put reflected light right at the edge or the edge vanishes. Bring it slightly inside and darken the edge so it shows. As the background darkens around the form, move the reflected light back to the very edge to keep contrast.

## Body shadows
- The body shadow is the shaded part of the object. It is distinct from the cast shadow.
- Halftone "H/T": the area where the form starts turning away from the light.
  - Make it very light and let it grade softly into shadow with no perceptible edge. Smudge with a finger if needed.
  - Halftone and shadow follow the curve of the form at right angles to the light.
- Shadow gets gradually darker on rounded forms the farther the surface turns from the light.
- Core of the shadow "core": the single clearly darkest band on a rounded object, directly opposite the lightest light and next to the reflected light.
  - It occurs only on rounded objects. Flat planes have no core.
  - Keep a soft, blurred transition between the core and the reflected light.
- Flat sides get an even tone, not a gradient.

## Sphere: order of steps
1. Draw a light circle 2–3 inches across and the table line.
2. Add the light arrow and the cast shadow.
3. Shade the wall behind the sphere down to the table edge in medium gray, and the table in light gray.
4. Fill the cast shadow, darkest under the sphere, and label "C/S".
5. Label "L", "H/L" and "R/L" (reflected light in light gray).
6. Add halftone "H/T", then gradually darker shadow up to the reflected light, with the "core" beside it.
7. Refine contrast and edges.
8. Circle lost edges and label each "lost edge". They help the eye travel from the form into the surroundings and knit the composition together.

## Cube, light from above left
- Construction: draw a "Y" and repeat the upper angles at its bottom. Draw the vertical side lines. Draw the top, repeating the angles in the same directions. Add the table and cast shadow.
- Top and left side face the light, so both are "L". Where two light planes meet, the edge disappears, and that is a bad place to lose it.
  - Fix: put a very light smudge of tone along one side of the edge, down the side or across the top, just enough to show the edge.
  - Use the eraser with a paper shield to make the edge crisp. Mark the cheated tone with an asterisk.
- Right side is "H/T" in an even light gray. The shadow side is out of view, so there is no core.
- No highlight or reflected light is visible in this view, so leave them out.

## Cube, backlighting
- Light comes from above, behind and to the right. The cast shadow still extends directly away from the light.
- The top stays "L". The right side is "H/T" in light gray.
- The left side is in full shadow, a darker even gray, blending into reflected light at the bottom from the table ("R/L").
- No highlight and no core.
- Wall: medium gray. Table: light gray.

## Cylinder
- Construction: draw an ellipse, add two side lines, then connect the sides with a rounded line at the bottom. Add the table line.
- Light arrow above left. The cast shadow runs away from the light to the table edge. Wall: middle gray. Table: lighter gray.
- The flat top and the left curved side both face the light, so they merge. Smudge tone down the side of the edge (asterisk) to define it.
- A shiny cylinder has a highlight along the top edge, running down the side. (Painting it is covered in Lesson Four.)
- The right outer edge of the shadow gets light-gray reflected light. The wall must be dark enough behind it for it to show.
- Start the halftone where the form begins to turn away, and keep darkening to the core. Label all parts.

## Hollow cylinder
- Draw only the top portion, enlarged, with a smaller ellipse inside for wall thickness. No table or cast shadow.
- Shade the exterior exactly like the solid cylinder, and leave the center of the top empty.
- Interior lighting is the reverse of the exterior. Light from above left hits the inside right wall, so that is the lightest area.
- Work right to left on the inside: halftone first, then gradually darker shadow toward the left, with no reflected light.

## White-on-white eggs (optional)
- Place two eggs on a napkin with some folds. Use a constant light such as a table lamp and keep the first drawing very light.
- Draw only what you see, not what you expect. If you don't see an edge, don't draw it.
- Expect many lost edges, reflected lights and tone changes on the eggs. White objects don't always look white.

## Applying shapes to complex subjects
- Trees, vases, arms and legs behave as cylinders. Buildings behave as cubes. Many fruits, the skull and the eyeball behave as spheres.
- Example: a cottage has its front in light (except the eave's cast shadow) and its side in halftone.