From Thumbnail to Final: Inside a Professional Digital Illustration Workflow

A finished illustration hides most of the work that went into it. Behind a polished character portrait or book cover are a dozen thumbnails, a few rejected sketches, a carefully organized layer stack and some export decisions that determine whether the piece looks crisp on a phone or blurry on a printed poster. This guide walks through the workflow we use for commissioned digital illustration, stage by stage, with the settings, checklists and time budgets that keep a project predictable.

Everything here is software-neutral. Photoshop, Clip Studio Paint, Procreate and Krita all support layers, blend modes, selections and color management in some form. Menu names differ, but the process is the same.

1. The brief and research

The brief is where the project succeeds or fails. A good brief answers practical questions, not just “draw my character looking cool”. Before we start any commission, we make sure we know:

• Usage: Is it a phone wallpaper, a book cover, a printed poster, a convention banner, a game asset? Usage dictates size, aspect ratio, resolution and color mode.
• Dimensions and format: exact trim size, bleed, and whether the client needs space for titles or logos.
• Subject details: character names, ages, outfits, key props, expressions, and what must not change.
• Mood and style: two or three reference images of the feel they want, ideally from your own portfolio.
• Deliverables: file types, number of versions (with text and without, for example), and whether layered source files are included.
• Schedule and revision rounds: when sketches, color roughs and finals are due, and how many rounds of changes are included at each stage.

Research comes next: historical costume, architecture, animal anatomy, technology, whatever the image contains that you do not draw every day. Ten minutes of research at this stage saves an hour of repainting a sword the client says is “from the wrong century”. If you are on the client side of this process, our guide on how to commission an illustration explains what to prepare.

2. Reference gathering and photo reference ethics

Every professional uses reference. The skill lies in using it well and using it fairly.

Building a reference board

Collect references into a single board using a reference-viewer app, a pinned canvas in your painting program, or a simple folder. Sort them into groups:

• Character: client-supplied designs, previous art of the character, costume details.
• Pose and anatomy: photos of yourself (a phone on a timer is enough), pose apps, 3D mannequins.
• Lighting and color: film stills and photographs with the mood you want.
• Materials: metal, fabric folds, hair, foliage, water.

Using reference ethically

• Shoot your own whenever you can. Your own photos carry no rights questions, and they match the exact angle you need.
• Use licensed or free-to-use sources when you need something you cannot photograph, and check the license terms for commercial use.
• Do not trace or closely copy someone else’s photo or artwork for a commercial piece. Studying a photo for anatomy and light is normal practice; reproducing its composition is a copyright and reputational risk.
• Combine several references for each element so the final image is your own synthesis.

Fan art raises its own questions about using other people’s characters. We cover those separately in our fan art vs original art copyright guide.

3. Thumbnails: small, fast and many

Thumbnails are tiny compositional sketches. Their job is to explore options quickly, before you invest in any of them.

• Size: keep them small, about 5–8 cm on the long side in a sketchbook, or 150–300 px on screen. Small size forces you to think in big shapes rather than details.
• Aspect ratio: draw every thumbnail in the final proportions. A book cover thumbnail should already be 2:3, a social post 4:5, a badge a circle.
• Quantity: aim for 8–15 for a standard illustration and more for complex scenes or covers. The first three are usually the obvious ideas; the interesting ones come later.
• Tools: one hard round brush, three or four flat grey values, no erasing.
• Text space: for covers and posters, block in the title and author name areas now.

Pick your strongest two or three thumbnails, tidy them slightly so a non-artist can read them, and present those to the client. Offering one gives no choice; offering ten hands your job back to the client.

4. Rough sketch and client approval

Once a thumbnail is chosen, scale it up to the final canvas (see the next section) and develop a rough sketch. This is where pose, anatomy, perspective and expression get solved. It should be clear enough that the client can approve the content, but loose enough that changes are quick.

Before sending the sketch, check it against the brief:

• Are all the required elements present: outfit details, props, expressions?
• Does the composition leave room for text, crop lines and bleed?
• Does the silhouette read when you flip the canvas horizontally? Flipping exposes anatomy and perspective errors your eye has stopped seeing.
• Is the value plan clear? A quick greyscale tone pass on the sketch helps clients picture the final piece.

Get written approval at this stage. Changing a pose in a sketch takes minutes; changing it after rendering can mean redoing the whole piece. That is why our illustration services set out what counts as a revision at each stage.

5. Canvas setup: resolution, size and color profile

Ideally you set up the final canvas before the rough is scaled up. Enlarging a finished low-resolution painting adds pixels but not detail, so it is the most expensive mistake to fix late.

Two rules cover most situations. For print, work at 300 pixels per inch at the final printed size, including bleed. For screen, only pixel dimensions matter; the dpi number in the file is ignored by browsers and apps.

Many illustrators paint at 1.5–2× the final size for detailed line work and scale down at export. That is fine as long as your machine can handle the file and the brush sizes stay predictable. Check memory limits first: a tablet app may cap the number of layers available at large canvas sizes.

Color profile

• Work in RGB. Use sRGB as the working space for almost everything; it matches most screens and most web and print-on-demand pipelines.
• Embed the profile when saving, so other software interprets the colors correctly.
• Do not paint in CMYK. Soft proof against the printer’s profile near the end and convert only if the printer asks for CMYK files.

Our colour theory guide for illustrators explains gamut and soft proofing in more detail.

6. Layer organization and naming

A messy layer stack is fine for personal work, but on client work it costs you every time a revision comes in. When the client asks for a different jacket color, you want to find the jacket flats in seconds.

A structure that works for most character pieces, from top to bottom:

1. FX group: glows, particles, color grading adjustment layers, texture overlays.
2. CHARACTER group:
   • LINE (with a separate layer for line color adjustments)
   • LIGHT: highlights, rim light (Add or Screen modes)
   • SHADE: shadow passes (Multiply), ambient occlusion
   • FLATS: one layer per material — SKIN, HAIR, CLOTH_TOP, CLOTH_BOTTOM, METAL, PROPS
3. BG group: foreground, midground, background, sky.
4. REF / SKETCH group, hidden and locked.

Naming conventions that help:

• Use short, uppercase group names and descriptive layer names. “Layer 47 copy 3” helps no one, you included, three months later.
• Color-code groups if your software supports it: one color for character, one for background, one for effects.
• Use clipping masks for shading on top of flats, so shading never spills outside the shape.
• Delete empty or abandoned layers before delivering a layered file to a client.

7. Line art and flats

Line art

Lower the sketch opacity to 20–30%, tint it a light blue or red, and ink on a new layer above it. Practical points:

• Use stabilization or smoothing for long curves, but turn it down for short, expressive strokes.
• Vary line weight: thicker on the outer silhouette and in shadow, thinner on interior detail and in light.
• Rotate the canvas freely so every stroke is drawn in your natural hand direction.
• Close gaps in shapes you plan to fill with a bucket tool, or use a fill tool with gap closing.

Some styles, such as painterly and lineless rendering, skip clean line art and move from a tight sketch straight to color blocks. The rest of the workflow still applies.

Flats

Flats are solid base colors for each material, with no shading. Keep them on separate layers, one per material, with clean edges and no gaps. Two tips save a lot of time:

• Fill with a bright, obviously wrong color first, so missed pixels are easy to spot. Recolor afterwards with lock-alpha or a fill adjustment.
• Choose flat colors as a palette, checking them together in greyscale for value separation before you shade anything.

8. Shading, lighting and rendering

Shading and lighting passes

Decide on your light setup first: key light direction and color, ambient or fill color, and any rim light. Then work in passes:

1. Ambient shadow: a Multiply layer clipped to the flats, using one mid-value color tinted towards the ambient or sky color. Block in shadow shapes with hard edges.
2. Form shadow refinement: soften edges where forms turn gradually (cheeks, cloth folds) and keep them hard where planes change sharply (nose, jaw, hard-surface props).
3. Light pass: an Add, Screen or Overlay layer for the key light, plus highlights on reflective materials.
4. Rim and bounce: secondary light from behind or reflected from nearby surfaces.

Rendering

Rendering is the slow, satisfying stage where you paint on a new layer above the passes, refining edges, adding texture and pushing detail at the focal point. To keep rendering under control:

• Render in order of importance: face and hands first, then key props, then everything else.
• Vary edges. Sharp edges draw attention, soft edges push things back. Not every edge needs to be crisp.
• Zoom out often. Check the full image at 25% every ten to fifteen minutes. Detail that cannot be seen at viewing size is wasted time.
• Stop at the agreed level of finish. Over-rendering backgrounds is the most common budget overrun.

9. Effects and finishing

Finishing pulls the image together. Keep it subtle and keep it non-destructive.

• Color grading: adjustment layers (curves, color balance, gradient maps at low opacity) to unify the palette.
• Atmosphere: soft gradients or haze between depth layers to separate foreground and background.
• Glows and particles: magic, sparks, dust, bokeh, used sparingly and mostly near the focal point.
• Texture: a paper or canvas overlay at low opacity to soften the digital look.
• Sharpening: a light sharpen pass on the focal area only, applied to a merged copy.
• Final checks: flip horizontally, view in greyscale, view at thumbnail size, and check edges and bleed for stray marks.

10. Export settings

Always export from a copy, never by flattening your master file. Choose the format by destination:

For screen delivery, convert to sRGB if you worked in another space. For print, use the printer’s specification. Some print-on-demand services want sRGB files and handle conversion themselves, while traditional offset printers usually want CMYK converted to a named profile. When in doubt, ask, and soft proof before sending.

11. File backups and versioning

Losing a nearly finished commission to a corrupted file or a dead drive is entirely avoidable.

• Version, don’t overwrite: save numbered versions at each milestone, for example clientname_project_v01_sketch, _v02_flats, _v03_render, _v04_final.
• Save often: use autosave or recovery features, plus a manual save every 15–30 minutes. Large files can corrupt on a crash.
• 3-2-1 backups: three copies of important files, on two different kinds of storage, with one off-site or in the cloud.
• Folder template: keep a standard project folder with subfolders for brief, ref, wip, exports and delivered.
• Archive on delivery: once the client confirms receipt, store the final layered file, exports and the brief together.

12. Time budget per stage

Estimating time is what lets you price commissions sensibly. The split below is a typical starting point for a single-character illustration with a simple background. Your own numbers will vary with style, so track your hours for a few projects and adjust.

Two patterns are worth noticing. First, the stages before line art take about a quarter of the time but decide almost everything about how the piece turns out. Second, rendering is the largest single block, so a late change of pose or palette can easily double the project. A clear brief and firm approvals protect that block.

If you would like a structured, one-to-one walkthrough of this workflow using your own pieces, our drawing lessons and mentoring cover each stage. If you would rather have us do the work, you can send a commission request with your brief.

Frequently asked questions