Photo to stencil

How to turn a photo into a stencil

1. Open the photo. Tap Choose a photo, drop it on the box, or paste it. One subject, cropped close, on a plain background gives the cleanest stencil; crop it first if needed.
2. Choose the layers. One layer is a black-and-white stencil: move the threshold until the face or the shape reads. Two to four layers split the photo into that many tones, one stencil each.
3. Look at the red outlines. Each one is a piece that would fall out when you cut. With bridges on, they turn into lime bridges; the line under the picture says whether anything is still loose.
4. Fix the bridges by hand if you like. Tap a bridge to remove it, tap near a piece's edge to add one there. Set the width and how many per piece in the Bridges panel.
5. Set the real size and save. The SVG goes to a cutting machine or laser; the PDF prints at true size across A4 or Letter pages. Measure the 10 cm check line before you cut.

What it cannot do

• It does not cut the subject out of a busy background. There is no AI here: the whole photo becomes stencil. Crop close or clean the background first.
• Bridges are straight. They run the shortest way from a loose piece to the sheet; there are no curved or styled bridges.
• It does not drive a cutter. It saves a file (SVG, PNG or PDF) that your cutter's or laser's own software opens.
• Tones are measured by brightness only. Two different colours of the same brightness land in the same layer.
• PNGs over 16 megapixels are refused (for example 35 × 35 cm at 300 DPI), because a phone can run out of memory; choose a lower DPI.
• Kept on this device only. The photo stays in this browser until you tap Clear; it is not in your other browsers or devices.

Islands, bridges and why a plain black-and-white photo is not a stencil

A stencil is a sheet with holes; paint goes through the holes. Wherever the cut goes all the way round a part of the sheet, that part is an island and drops out: the middle of an O, a highlight in an eye, the space between an arm and a body. Then the paint goes through there as well and the picture fills in. This page finds islands the way the knife would: two bits of sheet hold each other only if they share an edge, not just a corner.

A bridge is a strip of sheet left uncut across the hole. Here each loose piece gets the shortest straight bridge to sheet that is already held; with 2 to 4 per piece, the others are spread round it. Nested pieces, like the pupil inside the white of an eye inside an eyelid, are tied to the next ring out. A bridge leaves a gap in the paint as wide as the bridge, so keep it as thin as the material allows: at 300 DPI a 2 mm bridge is 24 pixels, a 1.5 mm one 18.

For several layers, each tone level becomes its own stencil, and each is checked and bridged on its own, because a piece that is safe on one layer can be loose on the next. Every layer has the same 12 mm frame and four registration marks in the same corners, on paper and in the SVG, so the sheets line up. A 30 × 20 cm stencil with its frame is 32.4 × 22.4 cm, which prints on two A4 pages per layer with a 10 mm overlap.

Questions

Is there a free online photo to stencil converter?

Yes, this page. Open a photo, choose one threshold or 2 to 4 tone layers, and download an SVG cut file, a PNG or a PDF that prints at true size. There is no sign-up and no watermark, and the photo is processed by your own browser, so it is never uploaded.

Why does my stencil fall apart when I cut it?

Because a converter that only turns the photo black and white leaves islands: pieces of the sheet that the cut goes all the way round, like the middle of an O or the white of an eye. This page finds every one, outlines it in red and adds straight bridges of the width you set that tie it to the rest of the sheet, then checks again that nothing is left loose.

How do I make a tattoo stencil from a photo?

Choose 1 or 2 layers, tick Outline mode so the edges are drawn as thin lines, and tick Mirror if your transfer paper reverses the picture. Set the real size in cm or inches and print the PDF at Actual size; the 10 cm check line tells you the printer did not scale it. Bridges are switched off in outline mode because nothing is cut.

How do I make a multi-layer spray paint stencil?

Pick 2, 3 or 4 tone levels. Each tone becomes its own layer, darkest first, and each is bridged on its own. Every layer is printed or cut on the same sheet size with the same four registration marks, so you can line the sheets up with each other. Spray the lightest layer first and the darkest last.

Which file do I need for a cutting machine or a laser cutter?

The SVG. It is drawn in millimetres at the size you set and holds only closed cut lines, one group per layer, so the cutter's own software imports it at the right size and can cut each layer separately. The PNG at a chosen DPI is for software that traces pictures; the PDF is for printing and cutting by hand.