Why Does Krita Fill the Wrong Packaging Illustration Region When I Increase Colorize Mask's Gap-Close Hint?

Classify the opening before adjusting the hint

A packaging illustration may contain both accidental line gaps and intentional openings. An accidental gap interrupts a boundary that was supposed to enclose a color region. An intentional opening belongs to the design and may connect two regions visually or leave part of the background visible.

Colorize Mask does not independently know which openings are artistically intentional. Its algorithm analyzes the available line art and color key strokes. Gap close hint changes how gaps in those contours are recognized.

Krita documents that higher values attempt to close larger gaps, but too high a value can produce other errors. Therefore, if one region fills incorrectly after increasing the hint, the next action is to inspect the prefiltered line art rather than simply increasing the setting again.

Keep a copy of the approved line art and record the actual gap locations. Do not alter a brand illustration's intentional outline merely to make one automatic fill succeed.

Use the prefiltered preview as diagnostic evidence

Select the Colorize Mask and enable Edit Key Strokes to inspect its working state. Krita describes a prefiltering preview that can look like a blurred haze around the line art. This preview helps show how the algorithm interprets contour gaps.

Make controlled comparisons at a low hint, a modest intermediate hint and a deliberately higher value only where appropriate for investigation. Keep the same key strokes and source layer composition. After each change, use Update and inspect the actual filled regions.

Ask two separate questions: did the intended accidental gap stop leaking, and did another boundary become incorrectly connected or separated? A setting that repairs one contour but damages another is not a successful global solution.

For line art with large dark filled regions, Krita also documents Edge detection. That is a separate input interpretation control, not an automatic substitute for a suitable Gap close hint.

Hypothetical carton mascot with two kinds of gaps

Hypothetical illustration—not a Krita test: a carton mascot has a small accidental break in the outline of its blue hat. The illustration also contains an intentional opening between a scarf and the character's shoulder.

The illustrator initially uses a low Gap close hint and sees a proposed leak from the hat region. Raising the hint is a plausible test for the accidental break. However, a very high setting might alter the interpretation of the scarf opening or other narrow contours.

The worksheet records the hat gap as the target and the scarf opening as a protected boundary. The exact pixel values are intentionally left to the real artwork, because Krita's documented example values are illustrations of behavior, not universal recommendations.

If no single hint setting preserves both regions, correct the underlying line art or use a more deliberate coloring arrangement.

Approve the region map, not just a clean-looking fill

Compare the result against the approved illustration. Inspect small negative spaces, line intersections, interior details and the edges of color islands. A visually smooth color patch can still be wrong if it crosses a meaningful boundary.

Keep the Colorize Mask editable in the KRA until the color-region structure is accepted. Converting it to a paint layer should follow, not replace, the region review.

The GIMP Foreground Select article diagnoses foreground/background classification in a photograph. This guide concerns Krita's line-art contour interpretation and the specific tradeoff introduced by Gap close hint.

Record your own observations

The filled rows are illustrative examples. Use the blank row for your own files and observations.

Download the editable CSV worksheet

What the references establish

• Krita Manual — Colorize Mask: Documents Gap close hint, prefiltered line art, Update, key strokes and the warning that excessive gap closing can cause errors.