Guide · Updated September 2026

How to Flat Colors in Photoshop

Flatting is the step between inking and coloring: you break your line art into clean, separated regions of flat color that you can select, shade, and render later. Here's how flatting works in Photoshop — the manual method every comic colorist learns, plus the faster way with a dedicated flatting tool.

Step 1 · Prep

Keep your inks on their own layer.

Good flats start with clean line art on a dedicated layer. Flatting sits underneath your inks, so your original drawing is never altered — you're only building a color base below it. If your linework has small breaks where shapes should close, that's fine; you'll patch those as you go.

  • Put your line art on its own layer, above everything else.
  • Add a new flats layer below the inks for your colors.
  • Work at the final resolution so region edges stay crisp.
Inked comic line art on its own layer, ready to flat
Line artClean inks on a dedicated layer are the foundation of good flats.
Step 2 · Fill the regions

Give every shape a solid flat color.

Flatting means assigning one flat, solid color to each closed region — skin, hair, each piece of clothing, the background. The traditional way is to lasso or magic-wand a shape, fill it, and repeat for every region on the page. It works, but on a detailed page it can mean hundreds of manual selections, plus chasing gaps where color leaks through broken lines.

  • Use distinct colors per region so borders are easy to see.
  • Close small gaps in the inks so color doesn't leak between shapes.
  • Keep every fill fully opaque — flats are a base, not shading.
Step 3 · Refine

Fix gaps, joins, and splits.

No page flats perfectly on the first pass. A line that doesn't fully close will merge two regions that should be separate; a stray mark can split one region into two. Refining is where flats become clean: join pieces that belong together, split areas along a guide, and recolor a region without reselecting it by hand.

Why this matters: clean, fully separated flats are what make the rest of coloring fast. Every region becomes a reliable selection you can shade, gradient, and adjust without bleeding into its neighbors.

Flatte's Repair tools handle exactly this: Join merges fragments, Split separates connected areas along a guide you draw, and you can preview a repair before you commit to it.

Line art separated into clean flat color regions
Flat colorsEach region is its own separated, selectable flat.
Step 4 · Put flats to work

Turn flats into selections for rendering.

The payoff of flatting is speed later. Because each region is a clean area of solid color, you can Ctrl/Cmd-click a flat to load it as a selection, then shade, add gradients, or drop in textures — all clipped perfectly to that shape. That's why flats are worth the effort: they turn coloring from careful masking into confident painting.

  • Load a region as a selection to shade without bleeding.
  • Clip rendering layers to your flats to keep edges clean.
  • Reuse a reference palette to keep colors consistent across a page.
A quick checklist

Clean flats, every page.

  • Keep inks on their own layer; build flats below them.
  • Give every region a solid, distinct color.
  • Close gaps so color never leaks between shapes.
  • Join and split regions until each shape is fully separated.
  • Use flats as selections when you render and shade.
FAQ

Flatting questions.

By hand, a detailed page can take an hour or more, because every area needs its own selection and fill. A flatting plugin like Flatte does the first pass in a few clicks, so you only fix the areas that need it.
No. You can flat with the Magic Wand, Lasso and Fill. A plugin only saves time. See the best flatting tools for comics for a comparison.
So you can see the borders clearly and select any area later with one click. The flat colors are only a base. You change them to the real colors when you render.
On their own layer, below the line art. This keeps your line art untouched and lets the lines cover the edges of the flats.
Usually because of a small gap in the lines or the wrong fill settings. Read how to stop color leaks when flatting for five simple fixes.
Less flatting, more creating

Flat a Whole Page
In a Few Clicks.

Flatte turns your inks into clean, separated flat colors inside Photoshop, then gives you focused Repair tools for the areas that need a human eye. It's a workflow tool — not an AI generator — so you keep control of every color.