How to colorize manga: by hand and with AI

To colorize manga you either color it by hand in a drawing program or use an AI colorizer that adds color to a black-and-white page automatically. Hand coloring gives you control and takes hours per page, while AI colorizing takes seconds and needs checking. RuneManga's colorizer is in development, so this guide explains the methods in general.

Method 1: Coloring by hand

Hand coloring is how most official color editions and fan colorings are made. The usual routine in a drawing program is:

1. Clean the scan: straighten the page, fix the levels and remove dust.
2. Put the line art on its own layer, so that color goes underneath.
3. Fill flat colors for each area, one layer per object or character.
4. Add shadows and highlights on separate layers, in a consistent light direction.
5. Handle screentone: either keep it as shading or replace it with painted shading.
6. Check every page against the previous one so that hair, skin and clothes keep the same colors.

It is slow, but you decide every color, and the result matches your taste.

Method 2: AI colorizers

An AI colorizer is a model trained on pairs of black-and-white and colored images. You give it a page and it predicts a color for each area. Some tools run in a browser, some are standalone apps and some come as part of larger translator projects. Results vary by tool and by page.

• Automatic: you upload a page and get a colored page back.
• With hints: you add a few color dots or a reference picture to steer the result.
• With a reference page: the tool tries to match characters' colors to an example.

What to expect from AI colorizing

• Plausible but invented colors. The model guesses; it does not know a character's real hair color unless you tell it.
• Colors that drift between pages. A character can change colors from one page to the next.
• Trouble with screentone and dense patterns, which can turn into noise.
• Flat or washed-out results compared with professional coloring.
• Fast turnaround, which makes it good for a quick look and less good for a final look.

Which method to choose

• A cover or a single favorite page: color by hand, or use AI as a first pass and fix it.
• A whole chapter for personal reading: an AI colorizer, with spot checks.
• A page that is for sale or for publishing: check the rights first, and expect to finish it by hand.

Tools you may meet

For hand coloring, drawing programs with layers are the standard, and Krita is a free, open-source one. For automatic coloring, some browser extensions are built only to colorize manga, some translators such as Torii include a colorizer, and the open-source manga-image-translator project has an optional colorizer. Each differs in quality and in what it does with your images, so test a page and read the privacy page first.

Where RuneManga fits

RuneManga is a translator first. Its colorize mode is planned, not available yet. The plan is to run translation and colorizing in one pass. The order is chosen for quality: read the text on the original page, translate, erase the lettering, colorize the clean page and set the translation last so it stays crisp.

Questions

• Colorize manga with RuneManga (planned)
• Translate, colorize or both: which mode to pick
• How does AI colorize manga?
• Glossary