Layers and blend modes for painters who hate menus

Most painting apps hide their best tools behind a tiny dropdown that says "Normal". Open it and you get a list of twenty or thirty words, half of which sound like photo filters. It is easy to close it again and keep painting everything on one layer with a round brush. I did that for a long time. It works, right up until you want to change the shadow color on a face you spent two hours on.

You don't need the whole list. Four blend modes and two layer tricks cover nearly everything a painter does day to day. The rest can wait until you're curious.

What a layer actually is

A layer is a sheet of clear film over your canvas. Paint on it and the paint sits there, separate from everything above and below. Hide it and the paint vanishes. Lower its opacity and the paint fades. That's all.

The trouble starts when layers multiply without a plan. Thirty layers named "Layer 17" are worse than one layer, because now you can't find anything and you still can't change anything. The goal isn't more layers. It's the right few, each with a job.

I think of it the way I think about inking a comic page. Pencils, inks, flats, shading. Each pass has its own job, and I never shade on the ink layer. Painting works the same way once you name the passes.

The four blend modes worth learning first

A blend mode changes how a layer's colors combine with whatever is underneath. In Normal mode, the top paint simply covers the bottom paint. Other modes do math with the two colors instead. You don't need the math, only the behavior.

Mode	What it does	White on this layer	Black on this layer	Typical painting use
Multiply	Darkens, like stacking tinted glass	Disappears	Stays black	Shadows, shading over flats, glazes
Screen	Lightens, the opposite of multiply	Stays white	Disappears	Haze, glow, soft rim light
Overlay	Boosts contrast: darkens darks, lightens lights	Lightens	Darkens	Color punch, texture, warm or cool shifts
Color	Keeps the brightness below, swaps in this layer's hue and saturation	Removes color	Removes color	Recoloring a grayscale painting, fixing a hue

Multiply

Multiply is the one you'll use most. Paint a soft purple on a Multiply layer over a yellow shirt and you get a darker, slightly muddy yellow shadow, the way a real shadow behaves. White paint does nothing at all on Multiply, which is why it's ideal over line art: scan a pencil drawing, set it to Multiply, and the paper vanishes while the graphite stays.

A tip from the comic side: Multiply never makes anything lighter. If a shadow looks too heavy, lower the layer's opacity rather than painting it again.

Screen and Add

Screen is the mirror image. Black disappears, everything else brightens what's below. It's good for mist, dust in a sunbeam and the pale edge of light on a cheek.

Many apps also have Add (Photoshop calls it Linear Dodge (Add)). It brightens harder and blows out to pure color faster. I keep Add for things that actually emit light, like a lamp or a phone screen in a dark room, and use Screen for light that's just passing through air.

Overlay

Overlay looks at the layer below and decides per pixel: darken where it's dark, lighten where it's light. A 50% gray on an Overlay layer does nothing. That makes it useful for pushing contrast or tinting a whole painting slightly warm without crushing it. It's also the mode people overuse, so treat it as seasoning. If you turn the layer off and the painting looks flat and dead, the Overlay was doing too much of the work.

Color

Color mode keeps the light and dark values of the layers below and replaces only the hue and saturation. Paint a grayscale study first, add a Color layer on top, and brush in skin, sky and fabric. The values stay locked. It's a fast way to test color schemes, and it's how I fix a face that came out too orange: a Color layer, a slightly cooler skin tone, a low opacity.

One warning. Color mode on top of pure black or pure white shows almost nothing, since there's no saturation to keep at those extremes. That's normal, not a bug.

If you want the full list for one program, the Krita blending modes reference groups them by family and is a good read once these four feel comfortable.

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Clipping masks and alpha lock

These two tools solve the same problem: painting inside a shape without going over the edge. They solve it differently, and knowing which to grab saves a lot of time.

Alpha lock

Alpha lock (Photoshop and Clip Studio Paint call it locking transparent pixels) protects the empty parts of a layer. Once it's on, you can only paint where paint already exists. Fill a jacket shape on its own layer, turn on alpha lock, and now a big soft brush adds shading that stays perfectly inside the jacket.

The catch: it changes the original paint. If you shade a flat with alpha lock and later want the flat color back, it's gone, apart from undo.

In Procreate, a two-finger swipe right on a layer toggles alpha lock. In Krita, it's the small checkerboard icon on the layer row. Other apps put it on the layer panel too, usually as a padlock or checkerboard.

Clipping masks

A clipping mask is a separate layer that only shows where the layer below has paint. Put the jacket flat on one layer, add a new layer above, clip it to the jacket, and paint shadows on the clipped layer. They're confined to the jacket, but the flat underneath stays untouched.

That separation is the whole point. You can change the shadow layer to Multiply, drop its opacity, erase it, or recolor it, and the flat survives. You can stack several clipped layers on one base: shadow, light, texture.

Procreate has Clipping Mask in the layer options menu. Photoshop has Create Clipping Mask (holding Alt or Option and clicking the line between two layers is the quick way). Clip Studio Paint has "Clip to layer below". Krita does the same job with its inherit alpha toggle or a clipping group from the layer menu. The names change. The idea doesn't.

My rule: alpha lock for quick, final touches on small shapes. Clipping masks for anything I might want to change tomorrow.

A short workflow that stays tidy

Here's the stack I'd use for a simple painted object, like a red mug on a table, top to bottom:

1. Line art, Multiply, so the white around the lines disappears (skip this layer if you paint without lines).
2. Highlights, Screen or Add, clipped to the mug flat.
3. Shadows, Multiply, clipped to the mug flat.
4. Mug flat, Normal, one solid red.
5. Table flat, Normal.
6. Background, Normal.

Six layers. Each one has a job and a name, and nothing is shaded where it shouldn't be.

Worked example: the red mug

Light comes from the upper left. I fill the mug shape with a mid red on its own layer. Then a clipped Multiply layer above it, and I pick a dull blue-violet, not black, and paint the shadow side and the inside of the rim. On Multiply that violet turns the red into a deep, cool crimson, which reads far more like a real shadow than red mixed with black. (James Gurney's Color and Light explains why shadows lean cool far better than I can.)

Next, a clipped Screen layer. A pale warm yellow, soft brush, a stripe along the lit edge and a small hard dot for the shine. If it's too strong, I drop the opacity to around half and leave it.

The cast shadow on the table goes on its own Multiply layer above the table flat, not clipped to the mug, since it falls on the table.

Now the useful part. The client (or my own taste the next morning) says the mug should be teal. I select the mug flat, turn on alpha lock, fill with teal. Because the shadow and highlight sit on their own clipped layers, they still work. The violet shadow over teal gives a deep blue-green, the warm highlight still catches the edge. One fill, no repainting. If I'd painted all of that on one layer, I'd be starting over.

Naming, grouping and the merge question

A few habits keep this from turning into a pile of seventy layers:

• Name layers by object and job: "mug shadow", "mug light". Takes two seconds and saves ten minutes later.
• Group by object. A group for the mug, a group for the table, a group for the background. Collapse the groups you aren't working on.
• Watch group blend modes. In Photoshop, groups default to Pass Through, meaning the layers inside blend with everything below the group. Set a group to Normal and those layers only blend with each other. Krita and Clip Studio Paint have a similar pass-through setting on groups and folders. If a Multiply layer suddenly stops shading the background, check the group setting.
• Merge when you're sure. Once a part of a painting is done and approved, merging its layers is fine. The point of layers is flexibility while decisions are open, not keeping every decision open forever.
• Keep one rough layer on top called "notes" for arrows and scribbles to yourself. Hide it before export.

Painters who came from paper sometimes worry that layers make work feel stiff. It can happen if every stroke goes on a separate layer. My workaround is to paint loosely on a single "paint" layer above the flats for a while, then split things apart only when I know I'll need to change them.

Brush settings that work with these modes

Blend modes behave better with the right brush. A soft airbrush on Multiply gives smooth form shadows. A textured brush on Overlay gives surface grain. If your strokes feel too blunt or too faint on a Multiply layer, the issue might be your pen pressure rather than the blend mode, and adjusting your pressure curve often fixes it faster than switching brushes.

In Procreate, brushes have their own blend mode in the brush settings, separate from the layer's. That's handy but confusing at first: a Multiply brush on a Normal layer still darkens. If shading looks strange, check both. The Procreate brush basics guide covers where those settings sit.

Krita users get the same choice per brush in the toolbar dropdown. If you're new there, the Krita for beginners walkthrough explains the layer docker before you start stacking modes.

Questions people ask

Should shadows always go on Multiply?

Not always, but it's the best default. Multiply darkens in a way that keeps the color underneath, which is close to how real shadows work. Some painters prefer painting shadows in Normal mode with a picked color for more control. Try both on the same sketch and keep whichever you can edit faster.

Why does my Overlay layer do nothing?

Probably because you painted mid gray, or the layer below is very dark or very light. Overlay barely changes pure black or pure white. Try a more saturated color, or check that the layer isn't clipped to something empty.

Is a clipping mask the same as a layer mask?

No. A layer mask hides parts of one layer with black and white painting. A clipping mask limits a layer to the shape of the layer below. Both are useful. For painting inside shapes, clipping masks are usually what you want.

How many layers is too many?

When you can't find the one you need in a few seconds. For a single object study, five to ten is plenty. A full illustration might use more, grouped. Name them and the number matters much less.

Try the mug stack once with any object on your desk. Flat, clipped shadow, clipped light, then change the base color. Once you've watched the shading survive a recolor, the dropdown that says "Normal" stops looking like a menu and starts looking like a time saver.