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Aquarell brush basics: compare size and opacity in a nine-cell study
Compare brush size and opacity in a nine-cell exercise, distinguishing a single stroke, repeated colour buildup and layer opacity.
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Make comparable samples with one brush before deciding whether it suits line work or colouring. Aquarell brush size controls mark scale, while opacity affects coverage. Changing several settings together makes the cause of a difference hard to identify.
This exercise creates a nine-cell brush chart. It is neither a built-in test nor the best settings for one brush, but a reusable comparison method. Begin with an ordinary canvas, one drawing layer and one colour.
1. Prepare a comparable canvas
Create a white 1200 × 1200 pixel canvas, leave about 100 pixels around it and imagine a three-by-three grid inside. Light dividers are optional; do not spend the entire exercise drawing boxes. Keep zoom fixed so all lines are compared at one display scale.
Choose a brush you can identify clearly in the list and record its name. Tips vary in texture, edge and strength; this article assumes no specific named brush. Use a medium-dark blue or brown so low-opacity samples remain visible.
2. Keep opacity fixed and change only size
Open the current brush’s settings, sometimes through Brush Studio. If pixels are shown, try 8, 24 and 64 pixels. If the control uses a slider or other units, choose clearly different small, medium and large positions and record their actual values instead of forcing these examples.
Set brush opacity to 100%. In row one, draw three similar-length straight lines and three slow curves at comparable speed and pressure. A pressure-sensitive input device may affect results, but this exercise assumes no particular hardware capability.
Compare line-width consistency, thickening on turns and how endpoints finish. A larger brush is not necessarily suitable for broad colouring: sparse texture may leave gaps both inside and along the edge. Learn the brush’s character rather than making every brush behave like a solid marker.
3. Keep size fixed and change only opacity
Return to a medium size, such as 24 pixels. In row two, test 25%, 50% and 100% opacity. Make one single stroke in each cell and three repeated short strokes beside it, lifting and restarting each time to compare repeated coverage.
Repeated low-opacity marks usually make an area darker or more solid, depending on brush, blend mode and texture. Two 50% passes do not simply equal one 100% pass, since edges and overlap positions may differ.
Write the values beside the samples or in separate notes. Label after comparing, since writing may change brush settings that you then forget to restore.
4. Observe seams with crossing strokes
In row three, draw three sets of crossed lines at low, medium and high opacity. Check whether intersections darken. Seams may interfere with an even sky, but overlapping marks can help describe layered plants.
Try covering the same area with one long stroke and then several short ones. Record any difference. Later, choose long passes or overlapping sections according to the result rather than repeatedly undoing and assuming the colour has malfunctioned.
5. Turn the samples into practical choices
Choose three combinations from the study: fine line work, medium colouring and a broad base. First record the brush name, size and opacity. If your version has a familiar brush-favourites control, save them there. Otherwise, ordinary written notes preserve the findings without assuming a particular saving feature.
Draw another leaf with the selected combinations: a fine outline, medium colour and a broad brush tested elsewhere for base coverage. Judge whether they help the task, not merely look good in a chart. Restore your usual settings afterwards to avoid surprises next time.
Final checks
The nine cells should reveal at least two clear differences: line width from size and coverage from opacity. Reduce the canvas to approximate sharing size to check fine lines, then zoom in to distinguish tip texture from image pixels.
Export a PNG reference and retain the native canvas. If a sample is nearly invisible, first check the active layer, visibility and layer opacity before changing the brush again.
Add practical conclusions to the samples
Do not merely mark the prettiest cell. Write task-based notes such as “fine turns stay clear: good for veins”, “medium repeated coverage leaves seams: use carefully for sky” or “broad textured edges: useful for a rough base”. These help future choices and provide comparable criteria across brushes.
Questions and limitations
Why does a brush at 100% opacity still show pale texture?
Opacity does not switch off every tip detail. Brush texture, strength and input variation still affect coverage. Compare with a more solid brush instead of immediately assuming the control is ineffective.
Can lower layer opacity replace a low-opacity brush?
They differ. Layer opacity affects the whole composite layer; brush opacity affects each stroke. The tonal relationships built by repeated strokes remain when the layer is faded overall.
Can these values be copied directly to another brush?
They are a starting point, not a guarantee. Tip size, texture and dynamics differ, so make a fresh comparison before using another brush in finished work.
Sources and applicable version
Information checked on October 22, 2026, for Aquarell 1.0.5 (iOS / iPadOS 15.0 or later). See the official description and Apple release lookup; the interface may change with the version.