Add print crop marks
Generate thin crop marks at the four corners of your image, like those used in professional printing to indicate where to trim the final medium.
How it works
In printing, crop marks tell the printer where to trim the medium once printed, without having to draw directly on the final artwork. This tool enlarges the canvas around your image (white margin) then draws, at each corner, two small thin marks (one horizontal, one vertical) positioned in line with the edges of the image, with a slight gap so they never touch the artwork.
Why specify a DPI resolution?
The margins, gap, and length of the marks are entered in millimeters to stay independent of the image resolution, but must be converted to pixels to be drawn: the given DPI (generally the one planned for the final print, often 300) is used for this mm → pixel conversion.
Does the mark touch my artwork directly?
No, a small configurable gap (2 mm by default) intentionally separates the edge of the image from the start of each mark, in line with printing conventions, so the crop mark is never printed over the artwork itself.
100% local processing: the crop marks are drawn directly in your browser via the Canvas API — your artwork is never sent to a server.