Disclosure: This draft was generated with AI and checked against the cited primary sources, with a separate AI editorial review. It was prepared for the FrameSprite team, which has a commercial interest in FrameSprite. Proposed examples are not executed tests unless explicitly identified as recorded fixture results.
Separate color and coverage when an edge needs repainting but its cutout should stay fixed. Krita's Split Alpha can move a paint layer's alpha into a transparency mask. That gives you distinct places to inspect and edit the color image and the visibility boundary. It is useful for controlled repair, not an automatic fringe remover.
Key Takeaways
- Decide whether the defect is the edge's color, its transparency or both.
- Keep an untouched source before separating alpha and painting hidden areas.
- A correct native mask does not guarantee that invisible RGB survives every PNG export path.
Diagnose the edge over two backgrounds
Place the sprite over a light background and then a dark one. A colored rim can come from visible edge pixels, partially transparent pixels carrying the wrong color, or an incorrect downstream blending convention. Note whether the defect already appears in Krita before changing the source.
If only the game produces the rim, first compare its import and blending setup. Painting a dark outline to compensate can damage a source that was already correct. If the wrong edge color exists in the source, save a .kra copy and isolate one region to repair.
Separate alpha deliberately
The official Split Alpha manual documents Split Alpha > Alpha into Mask and the corresponding operation for writing the mask back as alpha. Inspect the resulting layer tree immediately. Keep track of which thumbnail receives paint.
A Transparency Mask controls visibility. Repainting the color layer and painting the mask are therefore different edits. For a fixed silhouette, retain the mask while correcting the underlying color. For a chipped cutout, edit coverage consciously rather than expecting color paint to extend the visible outline.
Krita's Basic Concepts explains this separation between image content and masks. Do not confuse it with alpha inheritance, which is a compositing relationship among layers rather than a dedicated copy of the layer's own alpha channel.
Use a small repair to test the decision
Consider an unexecuted example with green contamination along a gray blade. Preserve the original, split alpha on a working layer and correct one short edge segment. Keep the mask unchanged for that first comparison. Inspect the result over both backgrounds at native size.
If the shape changes, check whether paint went into the mask or whether another layer contributed visible pixels. If the shape stays fixed but the rim remains, inspect partially covered edge pixels and the actual corrected region. A color repair under fully transparent pixels cannot by itself change visible interior contamination.
| Defect | Edit to investigate | Acceptance observation |
|---|---|---|
| Wrong visible edge hue | Color layer | Hue improves without moving the cutout |
| Missing blade tip | Alpha mask and source geometry | Intended tip becomes visible |
| Rim only after import | Consumer interpretation | Source and runtime agree under matching backgrounds |
Verify the exported representation
Export the runtime image to a new filename and reopen it independently. Repeat the light/dark comparison. Krita's Split Alpha documentation also discusses special handling for retaining color in fully transparent regions. Do not assume ordinary layered compositing preserves those hidden values just because they exist in the native source.
Keep that distinction in the delivery notes: visible-edge correctness and hidden-RGB retention are separate requirements. Only require hidden values when your downstream pipeline actually depends on them.
For related diagnoses, see premultiplied versus straight alpha, alpha trimming around glows and alpha inheritance. This is a proposed repair workflow; no export or engine test is claimed.
Written by the FrameSprite Workflow Team. Send a correction.
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