# Crayon Picture Book — Style Prompt

> A picture-book page drawn live in wax crayon on toothy paper, with a watercolour wash that reveals what the crayon was hiding.
> References (grammar only): Raymond Briggs' *The Snowman* (1982) (hand-textured frames that breathe, wordless tenderness, a lyrical passage carried by one tune, still backgrounds with living figures). Copy none of its characters, song or imagery, and never name it in the film.

## 1. Essence, and what it is not

A children's picture book page **being drawn while you watch**: wax crayon on warm off-white paper, a limited box of crayons, child-logic perspective, colour that spills past the outline, and every line gently **boiling** because each frame is a fresh drawing. The tone is picture-book storytelling: tender, unhurried, music-led, a few lines of narration that are literally the words printed on the page. Any topic becomes **one page of a picture book that gets finished**: drawing and colouring are the plot.

It is not "cute vector art with a crayon filter": the look comes from **material physics** (wax sticks only to the peaks of the paper tooth, pressure decides how much of the tooth it reaches, watercolour is repelled by wax). Not a whiteboard explainer (no marker, no hand), not a watercolour painting (the wash is a guest, the crayon the host), not a chalkboard.

## 2. Materials & rendering

- **Paper**: warm off-white (around `#f4efe3`). The tooth is **anchored to the page** (it pans with the camera; on zoom two octaves cross-fade so grains stay ~1 px on screen), never screen-fixed: three octaves of value noise plus a horizontal fibre term. A final pass embosses it (lit top-left), less where wax filled the tooth. Low mottling ±2 %, warm vignette.
- **Wax adhesion (the core rule)**: every crayon layer is a canvas where RGB = colour and **A = pressure**; the shader deposits wax where `tooth > 1 − k·pressure` (soft edge). Light pressure = speckled peaks; heavy = almost solid, slightly darker.
- **Strokes**: ribbons with a low-frequency hand wobble (1–2 px), width ±15 %, tapered ends, a denser core and 1–2 thin streaks. Characters and buildings get the heaviest outline; refined "adult" objects about half.
- **Colouring**: back-and-forth zig-zag hatching with a visible gap, each pass at a slightly different pressure; **overshoot the outline by a few px**; a lighter cross-hatch pass on big areas.
- **Watercolour wash**: a separate density canvas multiplied over the page. Pigment pools at edges (density minus blurred density), granulates in the deepest pits, blooms with noise, and is **resisted by wax** (density × (1 − ~0.9·wax coverage)). Brush strokes are wide bands with bristle streaks and a darker wet leading edge while moving.
- **Occlusion**: a front part erases what is behind it inside its outline; characters "keep the paper white" behind them (a knock-out that restores paper and resets wax), the way a child draws the figure first and colours around it.
- **Characters**: a skilled adult imitating a child: round head (≈2.5 heads tall), dot eyes with a white-wax catchlight, pink cheeks, tube limbs, mitten hands, bold hair shapes; objects with faces get big eyes and eyelids. **Child perspective**: gable front + slanted side wall; people bigger than doors.

## 3. Colour logic

- **A box of about a dozen crayons, never more.** Outlines in one dark colour (indigo, dark brown, plum), **never black**. One white crayon reserved for wax resist.
- **At most one watercolour** per film, chosen for what it reveals (ultramarine for night, rose for dawn, sap green for rain). It never paints the characters.
- Saturated crayon on lots of bare paper; value comes from pressure, not extra hues. One accent on a character may echo the story.
- Example boxes: *seaside* — navy line, coral, sand, teal, turquoise, lemon, white; *orchard* — brown line, russet, apple red, mustard, olive, plum, cream, white.

## 4. Type & subtitles

- Subtitles are **the book's printed words**: a handwriting face (Patrick Hand, OFL), 50–56 px, in the outline colour, bottom-centre, each glyph tilted and offset, boiling on twos, written left→right in ~0.35 s, on a ragged knock-out patch of blank paper (never a dark box). Hold ≥ max(1.8 s, speech + 0.6 s); none during wordless music.
- Titles are hand-lettered on the page (Gaegu Bold or similar), written letter by letter. You can't fade crayon: a title leaves by the camera moving off it, a page turn or being coloured over.

## 5. Motion quality

- **Everything drawn steps at 12 fps** (lines, colouring, characters, boil seed); camera, the wash's leading edge and twinkles run at 24 fps.
- **Boil**: each stroke re-jitters offset (<1 px), wobble and hatching rows every 2 frames. Characters full, background lines ~0.6, background colouring still (it also halves the bitrate). Calm the boil to about half when the film goes quiet.
- **Drawing on**: lines reveal along their length in 0.4–0.9 s; colouring row by row; text letter by letter.
- **Acting**: substitution, a new drawing per pose on the beat; two key drawings alternate for a repeated action. Big simple poses; a child's drawing doesn't in-between.
- **Colouring is an action**: being coloured in *is* doing (a coat scribbled on = putting it on; pink scribble = blushing; a wash = night falling).

## 6. Camera grammar

The camera moves over a large page. A vocabulary, not a route; every move needs a reason. Opening and ending come from the topic.

| Move | What it expresses | Can serve |
|---|---|---|
| Locked full page | Paper before drawing; the whole picture | a beginning from nothing; a tableau; a reveal that needs the page |
| Push toward a character | "This one" | a title giving way; a feeling arriving |
| Locked medium close-up | Substitution poses act | comedy; a decision; a small failure |
| Tilt along a gaze | We see what they see | discovery; longing; something huge |
| Tight follow | The world draws itself ahead of the subject | a brave act; a path; building |
| Held wide while the brush moves | The material is the motion | a wash reveal; weather; day or night falling |
| Slow truck across the page | Reading left to right | a list; a sequence; a family |
| Pull out past the page edge | The page is an object | a book on a table; a fridge drawing |
| Page turn | New chapter, time jump | before/after; the next day |

Key figures ≥ 1/4 of frame height in close shots; keep bare paper at the bottom for the printed words. Transitions: drawing on, colouring over, the wash, a pan or a page turn; never a dissolve.

## 7. Sound palette

- **Small wooden and metal-toothed instruments, no strings or grand piano**: ukulele or nylon guitar, clarinet or bassoon (bass, humour), music box (can wind down with a pitch droop), glockenspiel or celesta (a note per uncovered sparkle), toy piano (one note per counted thing), flute or recorder as the singing voice, shaker and woodblock. A simple lilt; one theme can be held back and heard in full once.
- **Silence is a beat**: a full beat of nothing after a failure; a short breath before a wordless passage.
- **Foley follows the material**: crayon = stick-slip band-passed noise whose grain follows stroke speed (colouring = rhythmic swishes); wet brush = soft low-passed noise with bristle grain, panned with the stroke; felt puffs, fabric swishes, a sharpener, a crayon set down, a page turn (lift / whoosh / flap). Ambience: faint crickets or birds, room tone, a distant clock.
- **Mix**: music under narration, rising for wordless passages; metal voices get a gentle high lift. −14 LUFS.
- **Voice**: a soft, warm storyteller, short lines with breaths. Compress before EQ, cut the highs, de-ess, a warm near-field reverb far under the dry voice; a few dB over the bed, never louder. Whisper-check every line, dry and on the final mix. Avoid famous-book phrases.

## 8. Native moves

A menu: use the ones your story needs.

- **Wax resist.** White crayon is invisible until a wash passes; hide the payoff in plain sight from the first frame. *Fits content like:* a farewell message; a product's hidden feature; roots under a garden.
- **Drawn live.** The world draws itself just ahead of the hero. *Fits content like:* a bridge plank by plank; a journey map; a company timeline.
- **Colouring is an action.** *Fits content like:* a town lighting up window by window; a team putting on kit; fruit ripening.
- **Boil.** A held frame is alive; calming it quiets the film. *Fits content like:* a pause for thought; grief; rest.
- **Child logic.** Wrong perspective, faces on objects, numbers in the sky. *Fits content like:* a launch countdown; a talking house on insulation; a sun that clocks out.
- **It is a book.** Pull back to the object; turn the page. *Fits content like:* a year in review; a "chapter two"; a thank-you card.

## 9. Pitfalls of the medium

- Gaps between wash bands leave white stripes → overlap bands and cover all intended paper.
- Wavy band edges and wide light streaks read as hills → small high-frequency waviness, thin faint streaks (α ≤ 0.12).
- Light-pressure colouring goes muddy under a wash → pressure ≥ 0.8 or cross-hatch wherever the wash crosses.
- Text where the wash passes survives it (wax resists) → place it elsewhere or accept it.
- Characters vanish under a wash → composite them *after* the wash.
- Outlines over hair read as a headband → outline hair masses on their outer edge only.
- Knock-out drawn into a plain layer shows as grey crayon → use a dummy canvas.
- Page turn from rectangle strips shows a staircase → an affine transform per strip.
- Double vignette/emboss at a page-to-object transition → page with vignette 0, ramp the outer scene's in.
- Screen-fixed tooth bloats the file → anchor it, don't boil background fills, no ffmpeg grain.
- Reverb IR from unit-variance noise is hugely loud → scale wet to ~18 dB under dry.

## 10. Engine

In `demo/`: `gl.js` (WebGL2 compositor: paper, wax adhesion, knock-out, watercolour + resist, emboss/vignette/lamp), `crayon.js` (`line` ribbons with taper, streaks, boil; `fill` hatching with overshoot; `text`; shapes), `rig.js` (occlusion + knock-out parts, limb tubes), `sheet.js` (model sheets, `?test=model&page=…`), `end.js` (page on a desk, page turn). Draw your own character's model sheet with them before any shot. File map and commands: [DEMO.md](DEMO.md#build-notes).

## 11. Variation space

You decide the structure, the characters (or none), the page, the opening, the ending, the camera path, the pacing, the crayon box and whether there is a wash. All far from our demo:

- Structures: **a colouring-book page** (all outlines there from frame one; each idea colours one area); **a flip through several pages** (one stage per page, joined by turns); **two children, one page** (two crayon colours argue, then combine).
- Openings: **a finished page rubbed out** to begin again; **a crayon tip in extreme close-up** mid-stroke, pulling back; **a crumpled page being flattened**.
- Endings: **the page taped to a fridge** among others; **a last scribble** filling the frame with one colour; **a stray splash of water** finding the white-wax message.

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How our demo was made (story, shots, score, end card, build): [DEMO.md](DEMO.md). Read it after your treatment exists.