Scribble: Controlled Chaos¶

Hand a charcoal stick to someone in a hurry and tell them to draw a portrait in thirty seconds. What you get is Scribble: frantic, energetic marks that cluster in the dark areas and scatter in the light ones. No parallel lines. No geometric precision. No mathematical curves. Just raw, kinetic strokes that feel like a human hand was involved, even though they are generated by an algorithm.

Scribble is the anti-Linear. Where Linear is ordered and dignified, Scribble is restless and expressive. Where Linear says "engraving," Scribble says "sketchbook." It is the fill you reach for when precision would be wrong.

What It Looks Like¶

Short, irregular strokes scattered across the canvas, denser where the image is dark and sparser where it is light. Each stroke has its own angle, its own length, its own slight curvature. The cumulative effect resembles charcoal on paper, aggressive pencil sketching, or the tangled marks of a pen testing on scrap paper.

At low density, individual strokes are clearly visible, like a sparse gesture drawing. At high density, the strokes merge into a dark, textured mass in the shadows while remaining loose and airy in the highlights. The randomness is controlled: it responds to brightness faithfully, building tone through accumulated chaotic marks rather than through orderly line spacing.

When to Use Scribble¶

Charcoal and conte crayon effects: Dense Scribble on textured subjects (bark, stone, fabric) produces a convincing charcoal sketch.
Gesture and figure drawing: Sparse Scribble on a nude or action figure captures the energy of quick life-drawing sessions.
Expressive textures: Fur, hair, grass, rough surfaces: anything that benefits from chaotic stroke direction.
Emotional and psychological subjects: The agitated quality of Scribble conveys tension, anxiety, urgency. Use it when the subject matter demands emotional weight.
Mixed-media compositions: Scribble for textured areas (hair, clothing) combined with Linear or Trace for structured areas (skin, eyes). The two registers set each other off.
Abstract and non-representational art: At extreme settings, Scribble produces pure texture that barely references the source image.

Parameter Reference¶

Parameter	What It Does	Recommended Starting Values
Interval	Controls the average spacing between scribble strokes, in mm. Lower values pack more strokes.	0.5 mm for dense charcoal. 1.5 mm for moderate sketch. 4--6 mm for sparse gesture marks.
Angle	Sets the dominant stroke direction. Individual strokes vary around this base angle.	0° for generally horizontal scribble. 45° for diagonal energy. 90° for vertical marks. The variance around the angle is what gives Scribble its chaotic character.
Randomization	Controls how much individual strokes deviate from the base angle and spacing. 0--100%.	30% for directional scribble (strokes mostly follow the angle). 50--70% for balanced chaos. 90--100% for maximum disorder.
Dispersion	Controls perpendicular scatter of strokes from their baseline positions.	Low (5) for tight, controlled scribble. Medium (15--25) for natural sketch energy. High (40+) for explosive scatter.
Stroke Thickness	Brightness-to-weight mapping. Linear, Thick, or Thin modes.	Thick mode enhances the charcoal effect. Linear for balanced tonal rendering.
Smoothing	Controls curvature of individual scribble strokes. Low = angular. High = flowing.	10--20 for scratchy, angular marks (pencil on rough paper). 40--60 for smoother strokes (felt-tip or charcoal).
Image Threshold	Histogram handles for brightness range.	Full range for complete tonal rendering. Narrow to shadows only for a sketch-on-white effect.
Dynamic Color	Strokes sample source image colours.	Off for monochrome sketch. On with short segments (1--3 mm) for coloured scribble.
Multiplier	Scales overall stroke width.	1.0 default. 0.5 for fine pen marks. 2.0 for bold charcoal strokes.
Shear	Distortion angle applied to strokes.	0 default. Small values (5--10°) add a slanted, wind-blown quality.

Step-by-Step: Textured Photo with Energetic Scribble¶

This walkthrough transforms a photograph with rich surface texture (bark, fur, stone, or fabric) into an energetic charcoal-style sketch.

1. Choose your image¶

Select a photograph with strong surface texture. A close-up of tree bark, an animal portrait with visible fur, a weathered stone wall, or a heavily textured fabric. The texture gives Scribble something to work with: the brightness variations in the surface create natural density variations in the scribble marks.

2. Add a Scribble fill¶

Click + in the Layers Panel. Select Scribble. Chaotic strokes appear immediately.

3. Set the density¶

Interval: 1.0 mm. Dense enough to build continuous tone in the dark areas while remaining visibly scattered in the light areas.

4. Control the chaos¶

Angle: 45°. A diagonal base direction gives the scribble kinetic energy without committing to purely horizontal or vertical.
Randomization: 60%. Strokes deviate significantly from the base angle, but there is still a subtle directional tendency. The result looks like someone scribbling with a preferred hand angle.
Dispersion: 20. Moderate perpendicular scatter.

5. Shape the strokes¶

Smoothing: 25. Low enough to preserve angular, scratchy character. Charcoal marks are not smooth: they catch on the paper grain.
Stroke Thickness: Thick mode. Charcoal deposits more material in the shadows.
Multiplier: 1.5. Bold strokes for a heavy-handed charcoal effect.

6. Adjust the threshold¶

Full range Image Threshold for the textured subject. The natural brightness variation in bark/fur/stone provides all the tonal information Scribble needs. If the subject has a flat, uninteresting background, narrow the threshold to suppress it.

7. Evaluate¶

Zoom to 100%. The scribble marks should cluster densely in the dark crevices of the texture and scatter in the raised, illuminated areas. The overall impression should be "someone sketched this in charcoal, quickly and energetically."

If the marks feel too uniform, increase Randomization. If the density is too even (no distinction between light and dark areas), check your Image Threshold and increase the contrast of the source image.

8. Optional: Add a warm undertone¶

Duplicate the fill. Set the copy's colour to a warm brown or ochre. Reduce its Multiplier to 0.7 (thinner strokes). Offset its Angle by 30° from the first fill. The two overlapping scribble layers in different colours create the impression of a charcoal sketch with a warm-toned underpainting, a classic fine-art technique.

Creative Variations¶

Sparse Gesture Drawing¶

Minimal strokes, maximum energy. The look of a 30-second figure sketch.

Interval: 4--6 mm. Very sparse.
Randomization: 80%.
Dispersion: 30.
Smoothing: 40. Slightly smoother strokes suggest a flowing drawing implement (brush pen, soft pencil).
Multiplier: 2.0. Bold, confident marks.
Image Threshold: Narrow to darkest 40%. Only the strongest shadows generate strokes.

Apply to a figure photograph. The sparse, bold marks suggest form without defining it. The empty white space between marks is as important as the marks themselves. This is what art students spend years learning to produce, and Scribble generates it parametrically.

Dense Charcoal Mass¶

The opposite extreme: shadows become nearly solid with accumulated scribble marks.

Interval: 0.4 mm. Extremely dense.
Randomization: 50%.
Dispersion: 10. Tight clustering.
Smoothing: 15. Scratchy, angular.
Multiplier: 1.0.
Image Threshold: Full range.

The dark areas become a heavy, opaque charcoal mass. The light areas remain loose and airy. The contrast between solid shadows and scattered highlights creates strong chiaroscuro. Works best on dramatically lit portraits: Rembrandt lighting, Caravaggio subjects.

Scribble + Mask for Selective Chaos¶

Use Scribble for hair, fur, or foliage, and Linear for skin or smooth surfaces:

Layer 1: Linear fill, Interval 1 mm, Angle 15°. Mask to expose only the face and smooth skin areas.
Layer 2: Scribble fill, Interval 0.8 mm, Randomization 70%. Mask to expose only hair, clothing, and background.

The contrast between controlled parallel lines on the face and chaotic scribble in the hair creates a composition that reads as carefully observed illustration. The face is rendered with precision (Linear); the hair is rendered with energy (Scribble). Each fill plays to its strengths.

Wind-Blown Scribble¶

Apply Shear to tilt all strokes in one direction, as if blown by wind.

Shear: 15°.
Angle: 0° (horizontal base).
Randomization: 40%.
Dispersion: 25.

The strokes lean uniformly to one side while maintaining their chaotic character. Applied to a portrait, it suggests motion or wind. Applied to a landscape, it conveys weather. The directional lean gives the chaos a sense of purpose.

Coloured Scribble Pointillism¶

Dynamic Color on, short segment length (1--2 mm), dense interval (0.6 mm). Each scribble mark picks up the source colour beneath it. The result is a frenetic, Fauvist pointillism: thousands of coloured marks that build into a representational image. Looser and more energetic than Halftone pointillism, with more personality than Linear Dynamic Color.

Tips¶

Scribble needs contrast. If your source image is low-contrast, Scribble produces a uniform scatter of marks with little tonal variation. Increase your source image's contrast before importing, or use the Image Threshold aggressively to create contrast.
Randomization below 20% defeats the purpose. Scribble with low randomization is just a messy version of Linear. If you want controlled parallel strokes, use Linear with a small randomization value. Scribble should scribble.
Scribble is the best fill for organic textures. Fur, hair, grass, bark, rough stone, crumpled fabric: anything with natural irregularity aligns with Scribble's chaotic stroke patterns. Smooth, geometric subjects (architecture, product photography) usually look better with Linear, Circular, or Halftone.
Two Scribble fills at different angles create crosshatch chaos. The result is denser and more layered than a single fill, resembling the build-up of repeated charcoal passes. Use different colours (black and dark brown, for example) for a rich, multi-toned sketch.
Scribble exports as many short paths. Unlike Spiral (one path) or Linear (few long paths), Scribble generates a large number of short, individual strokes. This can make SVG files larger and slower in downstream vector editors. If file size matters, increase Interval to reduce total stroke count.
Scribble is the most "human" fill. It is the one that most convincingly suggests a hand was involved. If your goal is to produce art that looks hand-made rather than computer-generated, Scribble (alone or combined with Handmade) is your strongest tool.

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