LESSON 07 · DIGITAL FOUNDATIONS

This is the most important lesson in the course. Layers are the one thing digital gives you that paper physically cannot: the ability to keep your construction, your line, your colour and your light as separate objects that never destroy each other. Everything in the modules after this one assumes you think in a stack.

SOFTWARE

Finish first: L5, L6

• Photoshop open with the Layers panel visible (Window > Layers)
• One of your own line drawings, photographed or scanned, or a fresh sketch on a digital canvas
• 45 uninterrupted minutes — this one is worth doing properly

WATCH

Aaron Rutten — App-agnostic layers primer aimed at beginners, recorded on current software. Aaron Rutten is a clean, tablet-focused digital art educator - a good fit for an XP-Pen course.

PHLEARN — Teaches the layer stack, blending modes and non-destructive editing on a current Photoshop build - the mechanics the 2021 Marco Bucci demo relies on.

LozsArt — The same ideas shown inside ArtRage, so you can see that layers are not a Photoshop feature but a digital-art idea.

THE LESSON

Picture a stack of clear glass sheets with white paper at the bottom. You can paint on any sheet. Looking down through the stack you see everything at once, combined into one image. Take a sheet out and everything on it disappears while the rest is untouched. That is a layer stack, and there is no more to the idea than that.

The part beginners get wrong is transparency. An empty area of a layer is not white — it is nothing, and whatever is below shows through. Photoshop draws a grey chequerboard where a layer is empty so you can tell transparent from white. It matters the moment you erase: erasing leaves a hole, so what you see afterwards is the layer below, not the white you expected.

The order of the stack is the whole game. The Layers panel shows the top of the stack at the top of the list, and you can drag layers up and down freely. New layer is Layer > New > Layer, or Shift+Ctrl+N on Windows and Shift+Cmd+N on macOS; it appears directly above whichever layer is selected. Which is why 'nothing is appearing when I draw' is almost always 'wrong layer, or under an opaque one'.

You already have a workflow: rough construction in light pencil, refine, commit to darker line, erase the construction. The erasing step is a loss: everything the construction told you about where the shoulder sat and how the head tipped is gone, and if the finished line turns out wrong, what would have shown you why went into the eraser dust.

Digitally that step does not exist. Construction goes on its own layer, finished line above it, and when you are done you switch the construction layer off. It is still there — turn it back on next week when the pose looks stiff and you want to know whether the ribcage was wrong from the start. Nothing has to be destroyed to make room for what comes next.

The same logic runs through the drawing. Colour goes under the line, so it can never muddy your inking. A shadow you regret is one click from never having happened. You are not starting over; you are getting your existing process with every stage preserved. The standard stack, bottom to top: background, sketch, flat colours, shading, line art, light and effects. Learn that order as a default, then break it once you know why it works.

A blend mode changes the arithmetic used to combine a layer with the ones below; Normal simply covers what is beneath. Three modes do almost all the useful work.

Multiply darkens. It multiplies the layer's colours with what is underneath, so white becomes completely invisible and everything else darkens what it sits over. This is the mode for shadows and for scanned line art: photograph a pencil drawing, set that layer to Multiply, and the white paper vanishes while the graphite stays — so you can paint colour underneath and keep your line on top.

Screen does the opposite: it lightens, black becomes invisible, and it is the mode for glows, highlights and anything luminous. Overlay increases contrast by darkening darks and lightening lights, useful for pushing colour into a grey underpainting — and the mode most often overused, so treat it as a seasoning.

The blend mode dropdown sits at the top left of the Layers panel, with Opacity next to it. Opacity fades the whole layer — dial a shading layer back to 60% when a shadow turns out too strong.

The problem clipping solves: you have flat colour for a character's jacket on one layer, and you want to shade it without the shadow spilling onto the background or the face. Create a new layer directly above the jacket layer and use Layer > Create Clipping Mask, or Ctrl+Alt+G on Windows and Cmd+Option+G on macOS. The upper layer indents with a small arrow, and from then on it only shows where there is paint on the layer below. Scribble wildly across the whole canvas and only the jacket-shaped part appears.

This is how most professional colouring is done: one flat-colour layer per part, with clipped shading and light layers on each. Fast, impossible to get outside the lines, every piece still editable. You can clip several layers to one base, and unclipping restores the layer with nothing lost.

Two failures, opposite directions. Everything on one layer is just paper with extra steps. And 140 layers named Layer 47 copy 3 is a file you cannot navigate and therefore will not finish.

Four habits prevent both. Name every layer as you make it — double-click the name in the panel and type. Group related layers with Ctrl+G or Cmd+G, so a character's whole face becomes one collapsible folder. Merge only what you are certain about, since Merge Down (Ctrl+E or Cmd+E) is permanent once the file is closed. For a flattened version to paint over, use Stamp Visible — Ctrl+Alt+Shift+E or Cmd+Option+Shift+E — which makes a merged layer on top while leaving every original intact underneath.

Save the layered file, always, as .psd or .ptg — a .png of a finished piece is a photograph of the stack, not the stack. And moving work between ArtRage and Photoshop, use PSD: ArtRage imports and exports PSD keeping layers, blend modes and groups, so your structure survives the trip.

PRACTICE · 40 MIN

1. Open a 3000 x 2000 px canvas and make six layers, named bottom to top: background, construction, flats, shading, line, light.
2. On 'construction', rough out a simple subject in loose light strokes — a shoe, a hand, a mug on a table. Do not tidy it.
3. Lower the construction layer's opacity to about 30%, then draw finished line work on the 'line' layer above it.
4. Hide the construction layer. Your line drawing should now stand alone. Turn it back on and off a few times to feel what that is worth.
5. On 'flats', below the line layer, block in solid local colours for each part with no shading at all. Keep each part's colour on this one layer for now.
6. Create a new layer above 'flats', clip it with Ctrl+Alt+G (Cmd+Option+G), set it to Multiply, and paint your shadows. Notice the paint cannot escape the flats.
7. On 'light', set the layer to Screen and add two or three highlights where the light source hits hardest.
8. Drag the 'line' layer to the bottom of the stack and look at what happens, then undo. That is the order lesson, learned the fast way.
9. Group the shading and light layers together with Ctrl+G, name the group 'rendering', and hide the whole group at once.
10. Use Ctrl+Alt+Shift+E to stamp a flat copy on top, then save the file as .psd with all layers intact.

Done when: Your file has at least six named layers in a sensible order, at least one clipped Multiply layer and one Screen layer, one group, and a stamped flat copy on top — and you can hide any single stage and still have a working drawing underneath.

Download these and work along with the lesson.

CHECK YOURSELF

Answer out loud first, then open each one to compare.