Screen Tone LPI Preview at Actual Print Size

What this tool does

Give it a paper size, print resolution, lines per inch (LPI), density, angle, and dot shape, and it draws a screentone matching those settings at true (1:1) scale. Dot spacing and dot diameter are shown in both millimeters and pixels, alongside the coverage actually measured from the pixels drawn, so you can compare it against your intended density. Four test patterns — flat tone, gradient, overlay, and a line-art edge test — each answer a different question about how the tone will behave. It can also work out the effective line count when a screentone applied on a larger source page is printed smaller (a "reduced-print conversion").

• CSP support: Moiré in screen tones (Japanese) — Official reference; checked 2026-09-06
• CSP manual: Exporting files (Japanese) — Official reference; checked 2026-09-06

Where it fits in your workflow

• Sweeping the angle offset between two overlaid screentones to see whether moiré appears
• Using the test patterns to find the density at which dots blow out or clog, and to check whether thin lines get buried under a screentone

How to use it

1. Complete the actual-size display calibration near the bottom of the settings panel by matching the on-screen band to a physical ruler at 100mm, then save it. Skipping this step leaves the preview at an approximate scale.
2. Set the paper size, orientation, and print resolution to match your actual artwork.
3. Enter the line count (LPI), density, angle, and dot shape.
4. Switch between the test patterns to match what you want to check: flat tone, gradient, overlay, or the line-art edge test.
5. Look at the preview from roughly the distance you would view a printed page, then read the dot spacing, dot diameter, and measured coverage in the numbers below it.

What each setting means

Print resolution

The DPI of your artwork. It determines how many pixels the screentone's dot spacing occupies on the source page. Monochrome manga pages commonly use 600dpi.

Line count (LPI)

Lines per inch — how many rows of screentone dots are packed into an inch. A higher number means finer dots. Doujinshi black-and-white pages typically fall around 55–70 LPI.

Density

The percentage of the page the screentone dots cover. Past 50%, the polarity flips from printing black dots to punching white holes out of a solid fill, and the on-screen readout switches from dot diameter to a white-gap diameter to match.

Angle

The tilt of the dot grid. 45° is the angle where the dot pattern is least noticeable to the eye, and it is a reasonable default unless you are specifically testing an overlay.

Test pattern

Flat tone fills the whole area at one density; gradient sweeps density from 0% on the left to 100% on the right; overlay layers two screens at an angle offset; the line-art edge test applies a screentone over lines of different widths next to a solid fill.

Overlay angle

Only shown for the overlay pattern — the angle offset applied to the second screen. At 0° it matches a single screen exactly, which makes it a useful baseline for comparison.

Actual-size calibration

Matches 100mm on screen to 100mm in the real world. The saved value is shared with the screen ruler tool.

Reduced-print conversion

Choosing a source size and a print size calculates how much finer the applied screentone becomes (the effective line count) once it is printed smaller. It does not change what the preview shows.

How to read the numbers

• Dot spacing is shown both in millimeters and in pixels on the source page. The smaller the pixel value, the finer the dots are relative to your artwork's resolution — a warning sign that the resolution may be too low for the line count you chose.
• Measured coverage is the share of drawn pixels that actually carry ink. If it drifts far from your density setting, the on-screen scale is probably too coarse for the line count to render accurately.
• The moiré period is the spacing of the visible ripple pattern that appears when two screens are overlaid. A larger value means a more visible, larger-scale ripple.

Three ways to build the same tone in Clip Studio Paint

• To paste a ready-made tone material, open the Material palette, find a tone under Monochromatic pattern > Basic, and drag it onto the canvas. Once it lands, select the resulting layer and open the Layer Property palette to check its Frequency, Density, Angle, and Dot settings (dot shape), then change them to match the numbers you settled on here.
• To build one from scratch, choose Layer menu > New Layer > Tone, which opens the Simple tone settings dialog. Enter Frequency (lines per inch), Density, Type (dot shape — Circle, Square, Lozenge, and so on), and Angle, then click OK to create a tone layer with exactly those settings.
• To convert an existing filled layer into a tone, select it and turn on the Tone effect in the Layer Property palette. The same Frequency, Density, Dot settings, and Angle controls appear there, and you can revisit and change any of them at any time after creation.

Choosing a line count and carrying over the effective line count

60 LPI is the conventional choice for monochrome doujinshi pages — the dots stay visible without looking out of place, and it prints reliably. When a page will be printed smaller than the source, or when you want a more delicate gradation, raising it toward 85 LPI makes the dots less noticeable, but a higher line count also packs the dots closer together relative to your print resolution, raising the risk of clogging and moiré — check the dot-spacing-in-pixels readout here to confirm your resolution can support it before committing. The effective line count this tool calculates describes how fine the tone will look once printed at the reduced size, but the Frequency value you type into Clip Studio Paint's tone settings is based on the source (working canvas) size, not the printed size. For example, if a B4 source page is going to be printed at B5 and you want the effective line count to land around 60 LPI, set the Frequency on the source canvas to roughly 42–43 LPI.

How the numbers are calculated

Dot spacing in millimeters is 25.4 ÷ LPI, and its pixel equivalent on the source page is print resolution ÷ LPI. Dot diameter is derived by solving for the radius whose area matches the coverage within one cell: for a circle, radius = spacing × √(coverage ÷ π); for a square, spacing × √coverage ÷ 2; for a diamond, spacing × √(coverage ÷ 2). Past 50% density the polarity flips, and the punched-out area is computed from 1 − coverage instead. The moiré period comes from overlaying two screens of the same line count at an angle difference θ, using dot spacing ÷ (2 × sin(θ ÷ 2)) for the spatial-frequency difference between them. Because the dot grid is square, θ is folded into the 0–90° range and the smaller equivalent angle is used. The screen-to-real conversion defaults to CSS 96dpi and switches to your saved calibration once one exists. The canvas backing store is drawn at your monitor's real pixel density (devicePixelRatio) and only the CSS dimensions are matched to true size: at 60 lines the dot spacing is barely 1.6 CSS px, far too little to render the shape of a dot if one CSS pixel were one sample. The ceiling on how many pixels may be drawn is counted in real device pixels too, so a high-density monitor reaches the crop threshold sooner. The effective line count is the line count divided by the reduction ratio (print width ÷ source width) — printing a B4 (257mm) page's screentone at B5 (182mm) turns a 60-line tone into roughly 84.7 lines.

Accuracy and what this tool does not cover

How accurate the true-size display is depends entirely on whether you completed the actual-size calibration. Without it, the preview falls back to an approximation based on CSS 96dpi, which will not match your monitor's real pixel density. Changing your browser or OS display scaling will also throw off a saved calibration.

• Even drawn at real device pixels, the halftone grid and the pixel grid of your screen still interfere. A fine shimmer that no printed sheet would show can appear, and it shifts when you change browser zoom or move the window to another monitor. Read moiré together with the moiré period figure rather than from that shimmer alone.
• In the line-art edge test, any line thinner than one real device pixel is still drawn at 1px, so the thinnest few lines will look heavier here than they will print.
• Overlay only handles two screens. Three or more overlapping screens, and features like Clip Studio Paint's tone-scraping or gradient screentones, are outside its scope.
• It does not reproduce the actual halftone screening a print shop uses (such as FM screening) or the reproduction characteristics of specific output devices. If you need to check an actual image file against print requirements, use Print Preflight instead.

How your data is handled

Screentone rendering and coverage measurement run in your browser. Tone settings and screen calibration are saved to localStorage and restored next time. Settings included in a shared link can be read by anyone with the link, and opening it sends its URL to the hosting server. Use Clear calibration to remove the display correction.