The Complete Guide to Bleed for Doujinshi Printing in Clip Studio Paint

Bleed absorbs the drift in trimming

A print shop trims printed sheets down to the finished size to make a book. Trimming cuts through a stack of many sheets at once, so the exact cutting line shifts slightly from top to bottom of the stack, and where the blade enters moves it further still. If a manuscript only has artwork right up to the trim line, the moment the cut drifts outward, a blank white strip is left exactly where the artwork stopped. Bleed, the Bleed width, is the margin that lets artwork run past the trim line so this drift gets absorbed instead of showing up as a gap.

Turn that around, and the bleed band is territory that gets printed but never survives into the bound book. There is no point putting anything a reader is meant to see there, and leaving it blank means any outward drift shows up as white paper. Think of the job not as "make the canvas bigger" but as "extend the artwork at the outer edge into that band."

When to use 3mm versus 5mm

When you create a new canvas in Clip Studio Paint, this margin is set under Bleed width. The official manual lets you choose 5 mm or 3 mm, and there is no separate field called "extra margin" — it is the same width, described differently on the print shop's side and the software's side. If a print shop's instructions say "3mm bleed," set Bleed width to 3 mm and the two line up.

• If your print shop specifies a width, that value wins. Doujinshi print shops most often ask for 3 mm, and this site's preflight checker defaults its use presets to a 3 mm bleed too.
• If you cannot find a spec, choose 3 mm. For a B5 interior page, finished 182 × 257mm becomes a 188 × 263mm canvas (3 mm on all four sides adds 6 mm to both width and height).
• 5 mm is for extra room in the bleed, giving more artwork to work with past the trim line before a cut can drift out of it. For an A5 interior page, finished 148 × 210mm becomes 158 × 220mm.
• Building at either width gives the same book once the finished size matches — only the cut-away band's width differs. A manuscript built at 3 mm falls short at a shop asking for 5 mm, though, so read the spec before deciding.
• To enter a value other than 5 mm or 3 mm, Show all comic settings for the Project unlocks a field for typing it in directly.

Setting the bleed when you start a new canvas

1. Open File menu > New and choose the work purpose. For a printed manga this is Comic. Printing of fanzine, which handles a whole multi-page doujinshi as one project, is EX-only, so PRO users work from Comic instead.
2. Enter the size of the finished book under Trim size. The manual describes this field as setting the trim size and bleed width for a manga manuscript, where trim size is the area shown once printed — the book itself, not the book plus bleed.
3. Choose 5 mm or 3 mm for Bleed width. The canvas is built from the trim size plus this width on every side, so there is no need to calculate the paper size yourself.
4. Decide the area your panels sit inside under Inner border, using Set margin or Set size. Anything that must not be cut off should be placed with this inner border as your guide.
5. Match Resolution and Basic expression color to your print shop's spec. Basic expression color is Color, Gray, or Monochrome, and a rough guideline is 600 dpi for a two-tone monochrome interior and 350 dpi for color.

Once the canvas is created, turn on View menu > Crop marks/Inner border to display the trim position and inner border on screen. Change the dimensions later from View menu > Crop marks/Inner border settings, and Safety margin lives in the same menu.

Adding bleed to artwork that is already finished

Even a manuscript built at exactly the finished size can have bleed added afterward, using Edit menu > Change Canvas Size. Its dialog has Width, Height, Unit, and Reference point, and setting Reference point to the center expands the canvas evenly on all four sides.

1. Set Unit to mm, then enter finished width plus 6mm for Width and finished height plus 6mm for Height (for a 3 mm bleed). A B5 page becomes 188 × 263mm, roughly 4441 × 6213 pixels at 600 dpi.
2. Set Reference point to the center so artwork already drawn does not shift. Choosing top-left instead pushes the existing artwork to one side, with the new margin only added on the others.
3. The newly added outer band is still transparent, so extend your background fills, flat colors, and tones out to it. Skip this and the canvas is bigger while the artwork is not, so any drift in trimming turns straight into a white strip.
4. Update the trim position in View menu > Crop marks/Inner border settings to match the new dimensions so you can check the cutting line on screen.

What you should not do is create bleed by enlarging the whole page with Edit menu > Change Image Resolution. That matches the canvas's apparent dimensions, but also changes the artwork's size relative to the trim frame, so panels and dialogue placed inside the inner border shift outward too. Enlarging line art drawn at 600 dpi also lowers its effective resolution. What was missing was more artwork at the outer edge, not bigger artwork overall, so keep the enlarging to the canvas alone.

Drawing so the artwork reaches into the bleed

• Extend background flat fills, gradients, and tones out to the canvas edge on the same layer they already sit on. Splicing in a separate layer just to cover the bleed band risks a visible seam depending on exactly where the cut lands.
• Do not stop radiating lines or effect lines at the trim line — run them out all the way to the canvas edge. Stopping short means a cut that drifts outward leaves a visibly truncated line ending.
• For a panel touching the trim line (a full-bleed panel), extend only that panel's contents into the bleed band, not the panel border itself — fill the space past the border with artwork rather than stretching the border line.
• Decide in advance to "paint white" rather than "leave unpainted" for any area meant to stay paper-colored, so you do not accidentally export it as transparent. Transparency becomes paper white once printed, but exactly how it is handled varies with export format and compositing settings, so committing to white is safer.
• When artwork spans a two-page spread, the gutter side is not trimmed, but how much disappears depends on the binding. Keeping anything a reader is meant to see out of the center is a separate decision from bleed, and still needs to be made on its own.

Common mistakes

One last check on the file you actually export

Even once every setting matches, what reaches the print shop is the exported image itself. Load the PNG or JPEG into this site's preflight checker, and it cross-references it against the finished size, bleed, and required resolution you entered, then reports what share of the pixels around the outer edge are close to white or transparent. A large share is flagged as possibly missing bleed, and a heatmap shows exactly where along the edge it runs thin.

It also works out an estimated dpi by dividing the pixel count by the physical size of "finished size plus bleed," catching the combined mistake of exporting without ever adding bleed, which leaves the resolution short too. A mismatch against the dpi embedded in the file shows up as a separate warning. Everything runs inside your browser, and nothing is ever sent to a server.