How dark should the shadow be?

Dark enough to read instantly, and in the same hue family as the fill rather than grey. A shadow that is only slightly darker looks like a printing error.

Should there be a highlight too?

Not in this style. One shadow and one flat lit area is the whole system, and adding a highlight moves it towards anime cel.

Why not use a gradient?

A gradient reproduces badly at small sizes, it cannot be recoloured reliably, and it removes the shape decision that makes this style worth using.

Flat Shadow

hard shadow
cel shadow
one shadow shape

All the shading reduced to one hard edged shape in a single darker tone.

Draw this style

Opens an image model with the prompt in it. The price is on the page before you sign in.

What it is for

One shadow shape gives a flat drawing volume without adding any rendering, and because it is drawn rather than calculated it can be made into a good shape in its own right. That is a choice a renderer cannot make.

How it works

One darker tone, one shape, one hard edge. The shape is drawn to be handsome in itself, usually cutting diagonally across the form. The lit area stays entirely flat. There is no second tone and no occlusion anywhere.

When to use it

Use it for flat illustration that needs volume, and for anything that has to reproduce cleanly at any size. Avoid it when material matters, because one tone cannot distinguish skin from metal.

Told apart from its neighbours

Ramp Shading uses several bands rather than one. Anime Cel is this plus a second contact shadow and a drawn highlight. Toon Shaded calculates the same look from a real light in three dimensions.

Where it is used

It suits a vector illustration, a poster, an icon and any flat drawing that needs to look solid.

Animation clean up and vector illustration
Poster and editorial work

The prompt

Replace the blanks with your own character, keep the rest. Then run it on an image model.

<character>, flat shadow style, all of the shading reduced to exactly one shadow shape in a single darker tone with a hard edge and no gradient anywhere, the shape designed as a shape rather than calculated from a light, cutting across the form in a way that reads as a silhouette of its own, the lit area left completely flat, no secondary shadow and no ambient occlusion

Run it

What goes wrong

A soft gradient shadow comes back. Ask for one shape, one tone, a hard edge, and say the shape is designed rather than calculated.

Leave out

gradients, a soft shadow edge, a second shadow tone, ambient occlusion, a highlight

Watch for

Say the shadow is designed rather than lit. The shape should be interesting on its own, which is what separates this from a render with a hard light in it.

Questions

Design it as a shape first and check it reads on its own. A diagonal across the form usually beats an anatomically correct shadow, because it describes the volume and looks deliberate at the same time.