How to Create Random Brush Width Variation While Keeping Marks Fully Dense

Treat the brush as three controls: the shape of each stamp, its transparency, and the distance between stamps. Size variation changes the stamp’s dimensions. Opacity and flow change transparency or paint application. Spacing changes how far apart successive stamps appear. Keeping these controls separate makes troubleshooting much easier. Krita: Options, Krita: Opacity and Flow, Krita: Brush Tips

“Fully dense” needs a practical definition: the interior should contain solid color without pale patches or pinholes. Smooth edge pixels can still be partially transparent because of anti-aliasing. Photoshop documents its Brush tool as anti-aliased and its Pencil tool as producing lines without anti-aliasing. Choose according to the edge appearance your character artwork needs. Adobe: Paint with the Brush or Pencil tool

Before introducing randomness, make a uniform-width test stroke. If that stroke already looks faint or speckled, fix its coverage first. Otherwise, you will be adjusting width variation while also trying to diagnose an existing transparency problem.

Use a standard hard round brush as the starting point. Open Window > Brush Settings, where brush-tip properties and dynamics can be configured. Adobe’s documentation identifies this panel as the place to choose a tip and adjust its shape and spacing. Adobe: Create a brush and set painting options

Try this illustrative starting recipe:

1. Set the Brush tool’s Opacity and Flow to 100%.
2. Disable the options-bar pressure controls for opacity and size while establishing the baseline.
3. Enable Shape Dynamics. Set Size Jitter to 30%, Control to Off, and Minimum Diameter to 70%.
4. Disable Transfer, leaving transparency variation inactive.
5. Begin with other optional effects disabled and draw several test strokes.

These percentages are suggested tuning values, not a measured optimum. Size Jitter supplies random size variation; Minimum Diameter sets the lower size limit relative to the brush diameter. Setting Control to Off removes an additional input such as pressure or fade. Transfer separately controls opacity and flow variation. Adobe: Add brush dynamics

Check the options-bar pressure buttons even after configuring the panel: Photoshop exposes separate pressure controls for diameter and transparency there. Keep them disabled for a test in which randomness is the only intended variable. Once the result works, you can deliberately add pressure-controlled size if you want manual variation too. Adobe: Paint with the Brush or Pencil tool

Start with a simple Pixel Brush preset and open its brush editor. Under Brush Tip, choose a circular Auto Brush tip with a solid center. Set Density to 100% and density Randomness to 0%. Krita’s tip Randomness changes the randomness of density; it is a different control from randomizing size. Krita: Brush Tips

Use this setup sequence:

1. Set brush opacity and flow to 100%.
2. Disable sensor-driven variation in Opacity and Flow.
3. Enable the Size option and select Fuzzy (Dab) as its sensor.
4. Remove Pressure from Size if you want randomness alone.
5. Adjust the size response curve so its lowest output stays above zero; begin with a narrow output range.
6. Draw a continuous curve and inspect both the outline and the interior.

Krita’s Size option controls how size responds to sensors, rather than setting the base diameter itself. The manual explicitly describes using a fuzzy sensor for size. Keep the tip diameter appropriate for the character detail, then use the response curve to control the amount of variation. Krita: Options

Choose Fuzzy (Dab) when you want variation within a stroke. Choose Fuzzy Stroke when you want a random value for each new stroke, useful for separate decorative marks that should differ in size. Krita documents Fuzzy Stroke as per-stroke randomness, including for size variation. Krita: Sensors

Decide on the narrowest acceptable mark before increasing randomness. For a character outline, judge whether the narrow sections remain readable at the artwork’s intended display size. A setting that looks appealing when enlarged may produce distracting thin spots when viewed smaller.

For an illustrative calculation, suppose your base diameter is 20 pixels and you want a minimum diameter of 14 pixels. The lower limit is 14 ÷ 20 × 100 = 70%. In Photoshop, that gives you a concrete Minimum Diameter setting. It defines a lower bound, rather than predicting the exact visible width at every point in an overlapping stroke. Adobe defines Minimum Diameter as a percentage of the brush-tip diameter. Adobe: Add brush dynamics

Use that calculation as a design aid: choose the broadest mark first, choose the thinnest acceptable section second, and then tune randomness between those limits. Change one value at a time. If the outline becomes too uneven, reduce the variation or raise the minimum before changing transparency.

A brush can produce opaque stamps with visible gaps between them. When the problem looks like a string of circles or a scalloped outline, examine spacing. Krita defines spacing as the distance between brush stamps. Lower it gradually while testing the narrowest sections of your variable-width stroke. Krita: Brush Tips

In Photoshop, an illustrative starting spacing of 10% is worth testing for a simple round tip. Adjust upward or downward according to the actual result. Avoid assuming that the smallest possible setting is best: Adobe notes that lower spacing requires more processing and recommends increasing spacing as far as the desired appearance permits. Adobe: Improve painting and cloning performance

Keep scattering inactive during this test. Scattering introduces random stamp placement, which adds another variable when you are trying to evaluate width alone. Krita documents Scatter as random placement of brush dabs. Reintroduce it only if displaced marks are part of the intended character decoration. Krita: Options

Use the appearance of the defect to choose your next adjustment. This diagnostic order is derived from the documented separation between tip coverage, size, transparency, and spacing.

What you see	First check	Next action
The entire stroke looks translucent	Opacity and flow	Restore both to 100% and disable their dynamic controls.
Light input produces pale sections	Transparency pressure controls	Remove pressure from opacity and flow.
Small holes appear inside individual stamps	Tip coverage	In Krita, restore Density to 100% and density Randomness to 0%.
Separate circles or gaps follow the path	Spacing	Reduce spacing and repeat the same curve.
The interior is solid but thickness changes too sharply	Size variation	Narrow the size range or raise its minimum.
The center is solid with a soft fringe	Tip softness	Compare with a harder tip before changing opacity.

The transparency checks matter because high opacity alone does not remove low flow or sensor-driven changes. Krita defines opacity as stroke transparency and flow as individual-dab transparency. Its manual also documents that sensor-modified opacity and flow multiply in the current behavior introduced in version 4.2. Krita: Opacity and Flow

In Photoshop, opacity caps transparency within a stroke, while flow controls how quickly color builds toward that cap. A faint pass therefore calls for checking both settings before making repeated passes over the same line. Adobe: Paint with the Brush or Pencil tool

Make a small comparison area beside your character drawing. Draw one straight stroke, one broad curve, and several short marks. Repeat them with the same brush size after each adjustment. Inspect the narrowest sections, the color inside the marks, and the continuity around curves. Then view the marks at their intended display size.

Save the brush only after it produces the width range and coverage you want. In Photoshop, choose New Brush Preset from the Brush panel menu and include tool settings when you want the painting settings stored with it. Adobe documents this save option alongside preset creation. Adobe: Create a brush and set painting options

Return to the character artwork with a brush whose size variation has a deliberate lower limit. Keep transparency fixed, use a solid tip, and adjust spacing until the marks connect cleanly. Those three checks let you refine irregular outlines without losing the dense color that makes them readable.

• Adobe Photoshop — Add brush dynamics
• Adobe Photoshop — Paint with the Brush or Pencil tool
• Adobe Photoshop — Create a brush and set painting options
• Adobe Photoshop — Improve painting and cloning performance
• Krita Manual — Brush Tips
• Krita Manual — Options
• Krita Manual — Sensors
• Krita Manual — Opacity and Flow