Stencil maker, a photo you can actually cut.

A stencil maker turns a picture into two tones: parts you cut away and parts that stay. The hard part is the pieces that stay but are surrounded by cuts. The middle of an O, the pupil of an eye, or an island in a lake would drop out when you cut the sheet. This stencil maker finds those loose pieces and adds a small bridge to each one, so you get one sheet you can cut, paint through and lift in one go.

How to use the stencil maker

1. Drop a photo on the box, click it to choose a file, or paste one with Cmd+V or Ctrl+V.
2. Look at the preview. Black is cut away, white stays. Switch between Stencil and Original under the picture.
3. Move Threshold until the shapes you need are black and the rest is white. Press Auto threshold to go back to the automatic choice.
4. Raise Blur to drop fine noise, raise Smoothing to round jagged edges, and raise Remove specks to lose tiny dots.
5. Tick Show the bridges in red to see where loose pieces are joined. Change Bridge width, in millimetres at your print size, until the bars look strong enough for your material.
6. Set the Width of the stencil, choose A4 or US Letter, and press Download printable PDF. Or press Download PNG or Download SVG.

What the bridges do

After the shapes are made, the white pieces are labelled. A piece that touches the edge of the picture counts as the sheet. Every other white piece is an island. The tool grows outward from the sheet through the black parts, one step at a time. When it reaches an island, it turns the shortest path back to the sheet white, as wide as your Bridge width, and the island joins the sheet. Then the island starts growing too, so the next island can join to it. Every island gets one bridge, and the bridges are as short as the shapes allow. When you tick Show the bridges in red, you see them. The line under the picture tells you how many islands there were and whether any are still loose.

Bridges change the picture a little, because a bridge fills in a thin bar of a cut shape. That is how stencils have always worked. Use a wider bridge for card or acetate you cut by hand, and a thinner one for fine work. Bridge width is set in millimetres at the size you set for printing, so a bigger stencil keeps bridges of the same real width.

Solid shapes or outline

Solid shapes cuts away everything darker than the threshold. It is the right choice for portraits, silhouettes and logos. Outline only cuts thin lines where the photo changes quickly, with Line sensitivity for how many lines and Line weight for how thick. Outline stencils have many loose pieces, so leave bridges on. Tick Cut the light parts instead to swap the black and the white.

Even out the light

A photo with a bright side and a dark side does not split well with one threshold. Even out the light subtracts part of the local brightness, so shadows keep their detail. Start at zero and raise it in steps.

Removing the background

Tick Remove the background first to cut out the subject with the same AI model as the background remover. The background becomes plain sheet. Tick Cut a line around the subject to keep the silhouette when the subject is light against the white. The model can miss thin hair or glass.

Printing at real size

Type the width you want. The height follows the photo's shape. If it is larger than one sheet, the PDF is cut into pages with an 8 mm overlap, corner marks and a label such as "row 2, column 1". Print at 100% or Actual size, with scaling off. Each page has a 5 cm or 2 inch bar so you can check the scale with a ruler. Trim along the marks and tape the sheets together, then tape the stencil to your material.

Stencil materials

Thin card, acetate, freezer paper and vinyl are common. Cutting machines work from the SVG, where the black shapes are the parts to cut away. For a hand-cut stencil on card, keep the bridges wide enough that the card does not tear when you lift it.

For a shaded look instead of a cut stencil, try photo to sketch or posterize image. To turn a drawing into curves, use image to SVG.