New to halftones? Read this first
Mesh is the fabric stretched over your screen. A higher number means finer fabric with smaller holes. It is printed on the roll and usually on the frame.
A halftone is how a press prints a lighter shade. Ink is either there or it is not, so a 50% pink is printed as a grid of pink dots, half covered and half bare, exactly like a newspaper photo. Small dots read as light, big dots as dark.
LPI (lines per inch) is how many of those dots fit in an inch. Higher LPI means smaller dots. And here is the catch that this whole page is about: if the dots get smaller than the holes in your fabric, they fall through and disappear when you wash out the screen. So your fabric decides how fine your dots may be — not your taste, and not your printer.
LPI is not the same as DPI. DPI is the resolution of your printer or file — how many ink dots or pixels it can lay down per inch. LPI is how many halftone lines those dots are grouped into. A 720 dpi file can still only hold the line frequency your mesh allows; extra DPI buys smoother edges on each halftone dot, not a finer screen.
You do not have to work any of this out. Find your mesh number below and use the LPI next to it. If you use the tool, just pick your mesh and it sets everything for you.
Not sure what mesh you have? Look at the frame or the invoice from your supplier. In Europe it is often written as threads per centimetre instead: 43T, 61T and 90T are the same three screens as 110, 156 and 230.
| Mesh (per inch) | Threads/cm | Line frequency | Dots per cm² | Smallest dot | Tonal range |
|---|---|---|---|---|---|
| 110 | ≈43 | 24 LPI | ≈89 | 0.46 mm (0.018″) | 15–85% |
| 156 | ≈61 | 35 LPI | ≈190 | 0.28 mm (0.011″) | 12–88% |
| 230 | ≈90 | 48 LPI | ≈357 | 0.19 mm (0.0075″) | 10–90% |
Dot sizes are shown in millimetres with the inch equivalent in brackets, and the tool lets you work in either unit. Threads/cm is the European convention; a European supplier calls 156 mesh "61T". Smallest dot is the diameter at the low end of the usable tonal range. Dots per cm² is the line frequency squared, converted from inches.
Why mesh decides frequency
A halftone dot is not printed onto the shirt by itself — it has to survive three stages first. It is exposed onto emulsion, washed out, and then pushed through a woven mesh. That last stage sets the limit.
Picture a 156 mesh screen: 156 threads per inch means a thread pitch of roughly 0.16 mm (0.0063″) — the actual gap between threads is smaller still, about 0.10 mm, since the threads themselves take up part of that space. Now picture a 5% dot at 48 LPI: about 0.12 mm (0.0047″). That dot is smaller than the two thread pitches it needs to span. It has no thread to hold onto, so during washout it simply disappears, and on press the tone it represented is missing.
The working rule is that the smallest dot you intend to hold should span about two thread pitches, roughly three openings. Run the numbers in the table above and you will see every entry lands there. That is not coincidence — it is where the 4.5 divisor comes from.
Higher frequency is not finer printing
It is tempting to reach for the highest line frequency your printer can produce. Above the limit your mesh can hold, extra frequency does not add detail; it removes it. The fine end of your tonal range stops printing at all, and the picture loses its highlights while gaining nothing.
If you want finer detail, the honest route is a finer mesh, which then permits a higher frequency. The order matters: mesh first, frequency second.
Why the tonal range is clipped at both ends
Look at the last column of the chart. At 156 mesh the usable range runs from about 12% to 88%, not 0% to 100%. Both ends are cut for physical reasons.
The highlight end: below roughly 12%, the dot falls through the mesh as described above. Printing it is not optional — it is impossible.
The shadow end: above roughly 88%, the white gap between dots gets so small that ink bridges across it. The tone prints as solid, so 90% and 95% and 100% all look the same on the shirt.
Good software clips these ranges deliberately and tells you it is doing so, rather than promising tones your screen cannot hold. PrintFilmReady applies the clip automatically once you choose a mesh preset.
How many grey levels do you actually get?
The number of tones a halftone can represent is set by how many printer pixels fit inside one halftone cell: levels = (dpi ÷ LPI)² + 1.
| Film resolution | 24 LPI | 35 LPI | 48 LPI |
|---|---|---|---|
| 360 dpi | ≈226 levels | ≈107 levels | ≈57 levels |
| 720 dpi | ≈901 levels | ≈424 levels | ≈226 levels |
The eye distinguishes somewhere around 60 to 100 tones in a gradient, and a textile screen holds fewer. So 360 dpi is comfortably enough for 110 and 156 mesh. The one case where 720 dpi earns its longer render time is fine mesh with smooth gradients, where 57 levels can show visible banding.
Angles: why one angle is enough for spot colour
Process printing rotates each channel to a different angle to avoid the four screens interfering with each other. Spot colours rarely overlap in the same way, so a single angle is fine — but it must avoid 0°, 45° and 90°, which line up with the weave of the mesh and produce moiré. 22.5° sits clear of all three, which is why it is fixed at that value in PrintFilmReady rather than offered as a setting to get wrong.
Want to try it on your own artwork?
PrintFilmReady separates your file into inks and screens each one into a print-ready film, in the browser. Free while in beta.
Common questions
What LPI should I use for 156 mesh?
About 35 LPI. The general rule is mesh count divided by roughly 4.5, so 110 mesh suits about 24 LPI, 156 mesh about 35 LPI, and 230 mesh about 48 LPI.
How many halftone dots are there per square centimetre?
Dots per cm2 is the line frequency squared. At 24 LPI that is about 89 dots/cm2, at 35 LPI about 190, and at 48 LPI about 357.
What is the smallest halftone dot a screen can hold?
Roughly two thread pitches across (about three openings). In practice that is about 0.46 mm (0.018″) at 110 mesh, 0.28 mm (0.011″) at 156 mesh and 0.19 mm (0.0075″) at 230 mesh.
What halftone angle should I use for screen printing?
For spot colour work, 22.5 degrees. Avoid 0, 45 and 90 degrees because they align with the mesh weave and cause moiré.
Is 360 dpi enough for halftone films?
Yes for 110 and 156 mesh: at 35 LPI a 360 dpi film yields about 107 grey levels, more than a textile screen can hold. 720 dpi mainly helps with fine mesh and smooth gradients.
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