Pencil, colour pencil or line art, with a live preview. Runs on your device.
The tool turns a photo into a sketch with the colour dodge method found in image editors. It makes a grey copy of the picture, blurs that copy, then divides the grey copy by the blurred grey copy: each pixel becomes its grey value times 255, divided by the blurred grey value there, capped at 255. Where neighbouring pixels are alike, such as a wall or a clear sky, the result is white paper. Where a pixel is darker than its blurred surroundings, such as an eyelash, a window frame or the edge of a face, the result is a dark stroke. That is why the effect looks like a pencil following the outlines. The grey step uses the Rec. 709 weights, 0.2126 red, 0.7152 green and 0.0722 blue. The blur is three passes of a box blur on each axis, which comes very close to a Gaussian blur. Everything runs on a canvas inside this tab.
Detail sets the blur size as a share of the picture's long edge, from 0.25 percent at 1 to 2.5 percent at 10. A small blur keeps fine lines such as hair and brickwork. A large blur keeps only broad shapes. Because the size is a share of the picture, a small preview and a 4000 pixel file look alike. Line darkness bends the stroke tones with a curve: low values give a faint, light sketch and high values give heavy graphite. Paper grain subtracts a repeatable speckle of up to 30 grey levels, so the white looks like paper and not a flat screen. The same pixels always give the same grain. The grain is turned off in Line art, which has no greys.
Pencil gives grey strokes on white. Colour pencil keeps the stroke weight but tints each stroke with the colour of the photo underneath, darkened by about 45 percent, so a red jacket gets red strokes and a green hedge gets green ones. Line art keeps only the strokes darker than a cut-off and turns them pure black on pure white, which suits a colouring page or a tattoo outline. Darkness moves the cut-off from 120 to 240 out of 255. This is a tonal sketch of the whole picture. The page Photo to Coloring Page traces edges only, which gives cleaner outlines for children to colour but no shading.
The picture is drawn on a canvas in this tab, turned into a sketch there and saved again in the same format as the original. JPEG and WebP are saved at quality 92, and PNG without loss. Transparent areas are filled with white paper first, because a sketch needs a background. Location and camera details in the original are not carried over, and your original file is never changed. Pictures with a long edge over 4096 pixels, or larger than the canvas limit of your device, are made smaller before drawing, and the result shows both sizes. The sketch is made in a background worker, so the page stays responsive and Cancel stops it. The tool does not draw hatching, does not add a hand-made look to the lines, and does not use a model. It is plain arithmetic, so a face is not detected and faces get the same treatment as a wall.
A sharp photo with clear edges and an even background, such as a portrait against a wall or a building in daylight. A blurry or very noisy photo gives scribbly strokes, because noise looks like many tiny edges.
Lower Detail to 1 or 2. The blur is then about 0.25 to 0.5 percent of the long edge, so on a 3000 pixel photo it is only 8 to 15 pixels and fine texture survives. Raising Line darkness at the same time keeps those fine lines visible.
Choose Line art and set Line darkness around 40 to 60. The result is pure black on white with no greys, so it prints cleanly and children can colour inside the lines. For outlines of objects only, Photo to Coloring Page is the closer tool.
No. A PNG or WebP with see-through areas gets a white background, because a pencil sketch needs paper. A JPEG has no transparency to begin with. Remove the background first if you want only the subject sketched.
The preview is made from a copy of at most 480 pixels on the long edge, and the saved file is made at full size. The blur is a fixed share of the long edge, so the look matches, but strokes are finer in the large file. Paper grain is also finer, as it is tied to single pixels.
No. The sketch is made on a canvas inside this tab and no server receives your picture. The page counts visits with Google Analytics using rough size groups such as 1 to 10 MB, never a file name, an image or the settings you chose.