The Best Flatting Tools for Comics
Flatting is the slow part of coloring a comic. The right tool can turn hours of clicking into minutes. Here are the five main ways artists flat comics in 2026, what each one is good at, and how to pick the right one for the app you already use.
The five options at a glance.
Every tool below does the same job: it fills each area of your line art with its own flat color. They differ in how much of the work they do for you, how they handle gaps in the lines, and which app they run in.
| Tool | Works in | Gaps in lines | Price |
|---|---|---|---|
| Flatte | Photoshop 2022+ (Mac & Windows) | Close gaps setting, plus Join and Split repair tools | One-time purchase ($25 launch price, then $39) |
| MultiFill + Flatten Pro | Photoshop (Mac & Windows) | Works best on line art without anti-aliasing; gaps are fixed by hand | MultiFill is free; Flatten Pro needs a paid license |
| Clip Studio Paint fill | Clip Studio Paint | "Close gap" option on the Fill tool | Included with Clip Studio Paint |
| Krita Colorize Mask | Krita | "Gap close hint" setting | Free (Krita is free) |
| By hand | Photoshop or any app | You close every gap yourself | Free, but slow |
Full disclosure: Flatte is made by PixelRec, the team that writes this blog. We still list every tool we would honestly recommend, and we say when another tool is the better choice.
1. Flatte (Photoshop plugin)
Best for: Photoshop artists who flat a lot of pagesFlatte is a Photoshop panel. You select your line art layer, click Create flats, and every closed area gets its own flat color on a new layer. Your line art layer is never changed.
Two settings control the result. Close gaps (off, low, medium or high) closes small breaks in the lines so colors do not leak. Small details removes tiny areas you do not want as separate flats. You can flat the whole page or only a selection.
Flatte also has a Repair tab for the areas that come out wrong: Join pieces that belong together, Split an area along a line you draw, try new colors or colors from a reference image, and Protect finished areas. This is the main difference from older tools: you fix mistakes without starting over.
- ✓Flats from your line art layer in a few clicks
- ✓Gap closing and small-detail cleanup built in
- ✓Repair tools: Join, Split, Color, Protect
- ✓Not generative AI: it only fills your own line art
Watch out for: it needs Photoshop 2022 or newer, and it is a paid plugin. You can try the panel in your browser in the live demo.
2. MultiFill + Flatten Pro (Peltmade)
Best for: artists who know the classic Photoshop flatting methodMultiFill and Flatten Pro from Peltmade (formerly BPelt) are long-standing Photoshop plug-ins. MultiFill gives every area of the image a different color. Flatten Pro then grows those colors until they meet under the lines, so no black line art is left in the flats layer.
Peltmade says the plug-ins work in any Photoshop version since Photoshop 6, on Mac and Windows. They support 8-bit RGB or CMYK images. For best results you copy your line art to a new layer without anti-aliasing (hard pixel edges) before you run MultiFill.
- ✓MultiFill is free to use
- ✓Works in very old and very new Photoshop versions
- ✓Trusted by comic colorists for many years
Watch out for: Flatten Pro needs a paid license (the demo is limited to 1024 × 1024 pixels), there is no 16-bit support, and there are no repair tools. If two areas merge through a gap, you fix it by hand.
3. Clip Studio Paint fill tool
Best for: artists who already draw in Clip Studio PaintIn Clip Studio Paint you do not need a separate flatting plugin, because the Fill tool already does most of the work. Turn on Refer other layers so the bucket reads your line art while you fill on a flats layer. Turn on Close gap so small breaks in the lines do not leak. Area scaling pushes the color a little under the lines so no white edges are left.
- ✓Built in, no extra cost
- ✓Close gap and Area scaling help a lot
- ✓Fast once the tool is set up
Watch out for: you still click once per area, so a busy page takes time. Close gap sometimes needs cleanup. And it only works inside Clip Studio Paint.
4. Krita Colorize Mask
Best for: a free, open-source workflowKrita is free, and its Colorize Mask is a smart flatting tool. You paint small color hints inside each area, and Krita fills the areas for you based on the line art. A Gap close hint setting helps with small breaks in the lines.
- ✓Completely free
- ✓Fills many areas from a few hints
- ✓Good gap handling on clean line art
Watch out for: it works best with closed, dark, even line art. Large or complex pages can be slow, and the Krita manual suggests limiting the mask to the layer bounds on big pages.
5. Flatting by hand
Best for: learning, or one illustration now and thenThe classic method works in any app: select an area with the Magic Wand or Lasso, fill it, and repeat for every area on the page. It costs nothing and gives you full control. It is also the slowest way, because a detailed comic page can have hundreds of areas.
If you flat by hand, the two most useful guides are how to flat colors in Photoshop and how to stop color leaks.
Which flatting tool should you use?
Start with the app you already use. Switching apps just to flat rarely saves time.
- ✓You work in Photoshop and flat often: Flatte, or MultiFill + Flatten Pro if you prefer the classic plug-ins.
- ✓You work in Clip Studio Paint: use its Fill tool with Refer other layers and Close gap.
- ✓You work in Krita: use the Colorize Mask.
- ✓You flat once in a while: flatting by hand is fine.
You may also read about AI flatting research, such as the FlatMagic project presented at the CHI 2022 conference. Flatte is not AI. It does not guess or invent anything. It only fills the areas inside your own lines, so the result always follows your drawing.
Flatting tool questions.
We make Photoshop plugins for comic and illustration artists: Flatte for flatting and PixelRec Pro for timelapse recording. We write these guides from our own work in Photoshop.
Flat a Whole Page
In a Few Clicks.
Flatte turns your line art into clean, editable flat colors inside Photoshop, then gives you Repair tools for the areas that need a human eye. No generative AI.