# Aquarell colour sampling: keep touch-ups, shadows and details consistent

Language: en
Canonical: [Aquarell colour sampling: keep touch-ups, shadows and details consistent](<https://allluckly.cn/en/guides/aquarell-canvas-color-picking/>)
中文：[中文 HTML](<https://allluckly.cn/guides/aquarell-canvas-color-picking/>)
English: [English HTML](<https://allluckly.cn/en/guides/aquarell-canvas-color-picking/>)
Published: 2026-10-22T00:00:00+08:00
Modified: 2026-10-23T10:34:06+08:00
Author: Bison

Sample from existing colour areas rather than repeatedly guessing, and check deviations caused by transparent overlaps and edge sampling.

English translation of the [Chinese original](<https://allluckly.cn/guides/aquarell-canvas-color-picking/>), translated on 2026-10-23. The article body uses automated translation; app descriptions, historical reading notes and video subtitles receive separate editorial checks. Original publication dates, attribution, code and version notes are retained.

**An existing painted colour is the most direct reference for later touch-ups.** Aquarell publicly supports canvas sampling. Sampling stable swatches instead of repeatedly guessing in the colour panel reduces drifting colours during touch-ups.

This exercise covers three tasks: recover the main colour for edge repairs, choose related shadows and keep details coherent. Sampling returns the colour appearance at that point, not the original paint recipe automatically.

## 1. Prepare a suitable sampling area

Open a practice piece with colour and detail layers, or create a 1200 × 1200 pixel canvas with a green leaf shape and small shadow. Ensure an even interior colour area exists, rather than only translucent texture and crossing strokes.

Check layer and brush before sampling. Even a correct colour looks lighter when painted at low opacity. Separate colour selection from painting conditions rather than blaming sampling alone.

## 2. Sample inside the colour area

Use the canvas sampling control. First try a long press; if your version has a dedicated entry point, use it instead. Do not treat one hold duration or screen coordinate as universal.

Sample an even area inside the leaf, avoiding outlines, translucent edges, highlights and background boundaries. Confirm the preview matches the target before finishing. Zooming in helps placement but does not create real image detail.

## 3. Test the sampled colour with one stroke

Test on a separate layer or a small nonessential area before touching the real outline. Use reasonably stable brush coverage so texture does not masquerade as a colour mismatch.

If the test stroke is lighter, check brush opacity, colour alpha and layer opacity. If darker, check whether it overlaps existing colour or was painted repeatedly. Sampling the right displayed colour does not guarantee an identical appearance on every background and blend.

Once confirmed, repair the leaf edge with a smaller brush. Minimise repeated passes: fill a contour gap rather than repainting the whole leaf.

## 4. Develop shadows from the main colour instead of switching arbitrarily

Sample the main green, then adjust slightly darker or cooler for a possible shadow. Paint a nearby swatch, compare it beside the main colour, then test it on a separate shadow layer.

Initially aim only for “one value darker than the subject”, without entering precise numbers. Adjust brightness slightly if the interface offers it; otherwise use the wheel and preview. No particular colour model or advanced palette feature is required.

A gray shadow may have lost too much brightness and saturation; one resembling another leaf may have shifted hue too far. Return to the main colour and change one direction at a time for a clearer comparison.

## 5. Unify detail colours from the painting

For veins or cup edges, sample an existing dark area instead of choosing pure black each time. Details integrate more naturally, especially in soft, low-contrast illustrations.

Do not sample every detail as the same dark colour. Important outlines can be stronger and internal structure lighter. Finish one main line, zoom out and judge the rest. Sampling maintains relationships; you still decide the hierarchy.

## Final check: establish a sampling habit

Compare the repair with the original area for a new colour band. If present, check whether you sampled a translucent edge or repeatedly overlapped fresh strokes. Undo the recent repair if needed and sample a more stable interior location.

Keep several clean original swatches near the practice canvas edge and hide their layer before export. Next time, sample these instead of searching a textured, shaded subject. A native project is more useful for further investigation than a flattened image alone.

## Keep a clear reference for later touch-ups

On a test layer, place main, shadow and detail swatches and label their roles. Start there next time rather than sampling heavily overlapped artwork. Hide the test layer and inspect the final export so working swatches do not remain at the edge.

## Questions and limitations

### Why does sampling an edge produce a white-looking fringe?

An edge may already blend with a light background or contain antialiasing, so sampling there produces a paler colour. Sample a solid interior area, then check opacity and coverage.

### Can sampling recover the exact originally selected colour?

Not always. The canvas may combine layers, transparent overlaps and blending. Preserve the original choice in a palette or explicit swatch rather than relying on an arbitrary point in the final composite.

### Why does the sampled colour still paint differently?

Sampling only selects the colour; brush opacity, layer blending and the underlying background also affect the result. Test one stroke on a blank separate layer with a stable brush to isolate causes.

### Can I sample a reference photo this way?

This tutorial checks canvas sampling only. An image you are authorised to use may be placed on the canvas for visible-colour comparison. Separate floating references, camera sampling and automatic palettes are not assumed capabilities.

## 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](<https://apps.apple.com/cn/app/id1591340577>) and [Apple release lookup](<https://itunes.apple.com/lookup?id=1591340577&country=cn>); the interface may change with the version.

## Keep practising

- [Build a five-colour palette](<https://allluckly.cn/en/guides/aquarell-limited-palette/>)
- [Compare brush coverage](<https://allluckly.cn/en/guides/aquarell-brush-size-opacity/>)
- [Adjust layer opacity](<https://allluckly.cn/en/guides/aquarell-layer-opacity/>)