CMYK Halftone: Four Screens at the Real Print Angles
Cyan at 15, magenta at 75, yellow at 0 and black at 45 degrees, kept apart so the grids do not interfere. Those angles are not decoration; they are the reason four-colour print does not produce moire.
Drop images here
or click to browse · or paste with Ctrl+V
JPG · PNG · WebP · GIF · BMP · AVIF
The spacing of the dot grid. Fine rulings look like magazine print; coarse ones look like a newspaper or a comic.
Screen angles
The traditional angles, kept 30 degrees apart where possible. That separation is what stops the four grids interfering and producing moire.
Turns all four together, so their relative separation is preserved and the pattern stays moire free.
How much of the grey shared by all three colours is printed as black ink instead. Printers use this to save ink and keep shadows neutral.
Everything is printed onto this. A slightly warm off-white reads as newsprint.
Presets
Your photos are never uploaded. The separation and the screening both run inside this browser tab.
People also use
Everything this tool does
The real screen angles
Cyan 15, magenta 75, yellow 0, black 45, giving pairwise separations of 60, 30, 75, 30 and 45 degrees between the visible inks. Rotating them together preserves every one of those gaps exactly.
Inks multiply, they do not add
A full cyan dot over a full magenta one gives 0,0,131, the deep blue overprinting actually produces. An additive or averaging model gives something much lighter and wrong.
Dot area follows the ink
A dot carrying twice the ink covers twice the area, so the radius follows the square root of coverage. Getting this wrong makes midtones far too dark, and it is the most common halftone error.
Black generation as a real control
How much of the grey shared by all three colours is printed as black instead. At zero the shadows go rich and muddy; around sixty is what commercial print actually uses.
Paper colour
Everything is printed onto the paper you choose, so a slightly warm off-white reads as newsprint without any other adjustment.
Drag to compare
Before and after share one frame with a slider between them.
Completely deterministic
There is no randomness anywhere, so the same photo and settings always give the same separation.
Six purpose-built presets
Magazine, newsprint, comic book, no black plate, poster and rotated screens.
Batch with one ZIP
Separate a whole set with identical settings and take everything as a single archive.
Nothing is uploaded
No server, no queue, nothing to delete afterwards. Close the tab and every trace of the image goes with it.
What each control does
Screen ruling decides how visible the process is. The angles are fixed by tradition and by the maths of avoiding moire, so you rotate them together rather than individually. Black generation is the one that surprises people.
| Setting | What it does | Try | Good for |
|---|---|---|---|
| Ruling 4-7 | fine, magazine quality | black gen 50-70 | Detail preserved |
| Ruling 12-24 | coarse, newspaper | black gen 60-80 | Obvious process |
| Rotate all | turns the whole set | any | Matching a look |
| Black gen 0 | no black ink at all | any | Muddy, rich shadows |
| Black gen 50-70 | the usual print setting | any | Neutral shadows |
| Black gen 100 | maximum grey replaced | coarse rulings | Flat, poster-like |
| Warm paper | off-white | any | Newsprint feel |
4
separations
15/75/0/45
screen angles
0
files uploaded
Subtractive
ink overlap
ZIP
batch download
Free
no account needed
FlipMyFormat vs other halftone tools
| Capability | FlipMyFormat | Typical free tool |
|---|---|---|
| Files stay in your browser | ||
| Four separations at the traditional angles | ||
| Subtractive ink overlap, not additive | ||
| Black generation as a real control | ||
| Dot area proportional to ink coverage | ||
| Batch ZIP download without paying | ||
| No watermark on the output |
How four colour printing actually works
A printing press cannot vary how much ink it lays down at a point; it either puts ink there or it does not. Tone therefore has to come from dot size, which is what a halftone screen produces, and colour has to come from overlapping four separate screens of cyan, magenta, yellow and black. That immediately creates a problem: four regular grids laid over each other will interfere, producing large visible patterns that have nothing to do with the image, which is moire. The solution the printing industry settled on is to rotate each screen to a different angle, keeping them thirty degrees apart where possible, because grids that far apart interfere at a scale too fine to see. Cyan goes to fifteen degrees, magenta to seventy-five, black to forty-five, and yellow to zero, since yellow is the least visible ink and its unavoidable clash with the others matters least. That is why the angles here are fixed and why the rotation control turns all four together rather than letting you set them individually. The other thing worth understanding is black generation. In principle you do not need black at all, since cyan, magenta and yellow together make a dark neutral, but in practice that dark is muddy, expensive in ink, and impossible to keep neutral. So printers replace some of the grey component with black ink, and how much is a real decision with visible consequences. At zero the shadows go rich and slightly muddy; at sixty, which is roughly what commercial print uses, they are neutral and clean.
- 1
Add a photo
Drag it in, click to browse, or paste with Ctrl+V. Colourful subjects show the four separations most clearly.
- 2
Set the screen ruling
Fine rulings read as magazine print, coarse ones as newspaper or comic art. This is the main lever on how visible the process is.
- 3
Set black generation, then export
Around sixty percent is what printers actually use. Export PNG, because thousands of hard coloured dots are the worst case for JPEG.
Angles, dot area and subtractive ink
Thirty degrees apart, on purpose
Two regular grids overlaid at a small angle produce a coarse interference pattern, and the closer the angles the coarser and more visible it is. Separating the screens by thirty degrees pushes that interference to a scale finer than the dots themselves, where it disappears into the texture. The traditional set is cyan at fifteen, magenta at seventy-five, black at forty-five and yellow at zero, and the reason yellow breaks the thirty degree rule is that it is by far the least visible ink, so its clash with the others is the one you can afford. The pairwise separations that result are 60, 30, 75, 30 and 45 degrees between the visible inks, with the only two 15 degree pairs both involving yellow. Rotating all four together preserves every one of those gaps exactly, which is why the control turns the set rather than the individual screens.
Dots grow by area, and inks multiply
Two details decide whether a halftone reproduces tone correctly. The first is that a dot carrying twice the ink must cover twice the area, not have twice the radius, so the radius follows the square root of the coverage. Getting that wrong makes midtones far too dark, which is the most common error in halftone filters. The second is that inks are subtractive: a cyan dot printed over a magenta one does not add their colours, it multiplies, because each layer absorbs part of the light passing through to the paper and back. That is why cyan over magenta gives blue rather than a pale mixture, and it is why the model here multiplies each ink over what is already on the paper rather than blending toward it. We check the consequence directly: a full coverage cyan dot over a full coverage magenta dot produces 0,0,131, the deep blue that overprinting actually gives, where an additive or averaging model would produce something much lighter.
What people use it for
Comic and pop art
Coarse CMYK dots are the defining texture of mid-century comic printing and of the pop art that borrowed it.
Poster and print design
The look signals print rather than screen, which is often exactly the message.
Album and zine artwork
Newsprint dots on warm paper carry a strong lo-fi association.
Packaging design
A visible halftone suggests craft and traditional printing.
Editorial illustration
The texture reads as magazine and newspaper, which suits editorial work.
Teaching about printing
The clearest way to show why four plates at four angles are needed.
Screen printing preparation
Separations at proper angles are the starting point for a four colour screen print.
Retro and vintage design
Nothing dates an image to print-era graphics faster than visible CMYK rosettes.
Six tips worth knowing
Screen ruling is the main lever. Fine reads as magazine, coarse as newspaper or comic.
Leave the angles alone, or rotate all four together. Setting them individually is how you get moire.
Black generation around sixty is what commercial print uses. Zero gives rich but muddy shadows on purpose.
A slightly warm paper colour does more for the newsprint feel than any other single setting.
Colourful subjects show the four separations most clearly; a near-monochrome photo mostly prints as black.
Export PNG. Thousands of hard-edged coloured dots is the single worst content for JPEG.
Troubleshooting
There is a visible interference pattern
That is moire, and it should not come from the screens themselves since they are thirty degrees apart. It is usually interference between the dots and a repeating pattern in your photo, such as a striped shirt.
The midtones look too dark
That is what happens when dot radius rather than area follows the ink, and it is not what this does. If your midtones look heavy, try a lower black generation.
The shadows look muddy
Your black generation is low, so shadows are being made from three colours overlapping. Raise it toward sixty.
It looks like flat colour, not dots
Your screen ruling is too fine for the size you are viewing at. Increase the spacing, or view at one hundred percent.
Frequently asked questions
What is a CMYK halftone?
The way four colour printing reproduces a photograph. Each of cyan, magenta, yellow and black is screened into a grid of dots whose size varies with how much ink is needed, and the four grids overlap.
Why are the screens at different angles?
Because four regular grids overlaid at similar angles interfere and produce large visible patterns, which is moire. Separating them by thirty degrees pushes that interference to a scale too fine to see.
What are the traditional angles?
Cyan 15, magenta 75, black 45 and yellow 0 degrees. Yellow breaks the thirty degree spacing because it is by far the least visible ink, so its clash with the others is the one you can afford.
Are those angles actually used here?
Yes. The pairwise separations between the visible inks come out at 60, 30, 75, 30 and 45 degrees, and the only two 15 degree pairs both involve yellow, which is the ink you can afford to clash.
Why does dot area matter rather than radius?
Because a dot carrying twice the ink must cover twice the area, so the radius follows the square root of coverage. Making radius proportional to ink instead makes midtones far too dark, and it is the most common halftone error.
Why do the inks multiply?
Because printing is subtractive: each ink layer absorbs part of the light passing through to the paper and back. A full cyan dot over a full magenta one gives 0,0,131, the deep blue overprinting really produces.
What is black generation?
Cyan, magenta and yellow together make a dark neutral, but a muddy, expensive and hard to control one. Printers replace some of that shared grey with black ink instead, and how much is a real decision.
What black generation should I use?
Around sixty percent, which is roughly what commercial print uses. Zero gives rich but muddy shadows, which is a deliberate look rather than a mistake.
Why can I not set each angle separately?
Because the separation between them is what prevents moire, and setting them individually is how you break it. The rotation control turns all four together, preserving every pairwise gap.
I still see an interference pattern
It is probably between the dots and a repeating pattern in your photograph, such as a striped shirt or a mesh, rather than between the screens. Changing the ruling usually clears it.
How is this different from the halftone tool?
That one screens a single channel. This separates the image into four inks and screens each at its own angle, then overprints them subtractively, which is what actual four colour printing does.
Why does it look like flat colour?
Your screen ruling is too fine for the size you are viewing at, so the dots merge. Increase the spacing or check at one hundred percent.
What does the paper colour do?
Everything is printed onto it, so a slightly warm off-white reads as newsprint. It does more for a vintage feel than any other single setting.
Which format should I export?
PNG, and it genuinely matters. Thousands of hard-edged coloured dots is the single worst content for JPEG, which will blur them and add fringing everywhere.
Are my photos uploaded to a server?
No. The separation and the screening both run in your browser using the canvas API. Nothing is sent anywhere.
Can I use this to prepare a real print?
It is a good illustration of the process and a fine starting point for a screen print, but a commercial press needs proper separations from a colour managed workflow rather than a rendered image.
Can I process a batch?
Yes. Add as many photos as you like and the same ruling, angles and black generation are applied to each.
Does it add a watermark or need an account?
No to both. No sign-up, no email wall, no daily limit and no watermark on the output.