Photo to paint by numbers

How to make a paint by numbers from a photo

1. Open the photo. Tap Choose a photo, Take a photo, drop a file or paste one. A close crop of one subject, evenly lit, works best: a face, a pet, a house, a single flower.
2. Pick the sheet. A4, A3, Letter, an 18 cm square, or Canvas size in cm or inches. The photo is cropped to that shape; slide Crop position to keep the part you want.
3. Pick the colours. 6 to 36. The painted preview beside the sheet shows what you will end up with. Swap a colour for one you already own, merge two that you would paint the same, or lock one you like before trying other colours.
4. Set the detail. Smallest region is measured in mm² on the printed sheet, so 12 mm² is about a 3.5 mm square, the size a fine brush can fill. Smoothing removes speckle before the regions are drawn.
5. Add your paints. Under My paints, tap dabs on a photo of a swatch card or type HEX codes, and name each tube. Every number gets a mixing recipe from those paints.
6. Print it. The PDF prints the outline at true size, over several pages with overlap lines if the canvas is bigger than the paper, and a colour key page with each number's recipe. PNG and SVG hold the outline alone.
7. Or paint it on screen. Paint on screen opens the numbered sheet full screen with the key as a bar of numbers. Pick a number, then tap its areas to fill them; pinch or scroll to zoom, drag to move. The counter and the ticks show what is left, and the progress is kept on this device, so you can stop and carry on later.

What it cannot do

• A recipe is a prediction from the colours you gave. Real pigments, brands, how much water or medium you add and drying all shift it, so mix a small dab first and adjust. The model guesses each paint's spectrum from its screen colour, not from measured pigment data, so two tubes that look alike on screen mix alike here even when they do not in the pot. Printed and screen colours also differ.
• It cannot tell tubes apart by brand or name from a photo. It only sees the colour of each dab you tap, and a phone camera's white balance shifts that colour, which is why the card should be shot in daylight on white paper. You type each name yourself.
• Busy photos make many small regions. Leaves, gravel, crowds and hair can give hundreds of regions even at the minimum size. The page says so when it happens; fewer colours, more smoothing or a bigger smallest region help, and a tighter crop helps most.
• It is not a printed kit. You get a file to print or trace onto canvas, not a pre-printed canvas, paint pots or brushes.
• Smooth outlines bend the border by up to 0.25 mm, so very thin strips can vanish. The regions are worked out on a grid about 1,000 pixels on the long side (a pixel is about 0.28 mm on an A4 sheet, 0.8 mm on a 60 × 80 cm canvas). Smooth, the default, replaces each border's pixel steps with cubic curves that stay within 0.25 mm of the lightly smoothed border on the printed sheet; the two regions either side share that one curve, so there is no gap and no double line. A region or a neck thinner than about twice that, 0.5 mm, can close up and merge visually into its neighbour; the minimum region size and number height keep most regions far wider than that. Pixel keeps the exact grid steps instead.
• Your sheet is kept on this device only, not across devices. The photo, settings and colour changes stay in this browser's storage; another phone, another browser or a private window starts empty, and clearing the browser's site data deletes them. Nothing is uploaded, so there is no copy anywhere else.
• On-screen painting is kept on one device, for one sheet. The filled areas are not synced to another phone or computer, and changing the photo, the number of colours or the detail draws different areas, so the progress is reset (the page says so when it happens). It is tap-to-fill, not brushwork: there is no brush, blending or painting over a line.
• Easy is for small hands, not for every photo. Eight colours turn a detailed scene into flat patches; a face can lose its features. A big, simple subject (a pet, a toy, a car, one flower) keeps its shape best.

Easy, Standard and Detailed

The three buttons above the controls only move the sliders; you can change any of them afterwards, and the row then shows Custom. Easy is for children: fewer colours, bigger regions, more smoothing, a thicker line and bigger numbers.

The number size is a digit's height on the printed sheet. Every number grows with its region (1.4 times the distance from its centre to the nearest line, up to a 5 mm font) and is never shorter than the smallest number above. On Easy, any region narrower than that 2.5 mm digit is merged into its neighbour, so the number fits inside. 60 mm² is about a 7.7 mm square, room for a child's brush to fill without crossing the line. On an A4 sheet a simple photo on Easy usually gives tens of regions rather than hundreds; the difficulty line under the sheet shows the real count.

Colours, detail and what to expect

The colours are found by k-means clustering in OKLab, a colour space where equal distances look like equal differences, so a dark green and a dark blue are not lumped together just because their RGB numbers are close. The start is seeded, so the same photo and settings always give the same sheet; Try other colours uses another seed.

The difficulty line counts what you will paint. As a rough guide, an A4 sheet with up to about 250 regions is a first-timer's afternoon, 250 to 700 is a few evenings, and more is a long project. Each number is placed at the point inside its region farthest from any line, so it never sits on an outline (with Smooth outlines every number is checked again against the curved border and moved to the region's new most interior point if a curve would cross it); very thin strips that cannot hold a number are merged into their neighbour.

Mixing recipes from your own paints

Screen colours add light, paint takes it away. Average the RGB numbers of a yellow (#FFC800) and a blue (#1E3CA0) and you get #8F8250, a khaki grey; mix the two paints and you get a green. The recipes here use spectral.js, which turns each colour into a reflectance curve over 38 wavelength bands and mixes those the way the Kubelka–Munk model mixes pigments, so the same yellow and blue at 1:1 come out as #67973A, a leaf green.

For each number the page tries every mix of one, two or three of your paints in whole parts adding up to 12 or fewer: 196 part splits for every set of three paints and 45 for every pair, 46,102 mixes for a full list of 12 paints, done once when the list changes. It keeps the mix whose colour is nearest the key colour in OKLab, and if a simpler recipe (fewer paints, then fewer parts) is within 0.004 of it, the simpler one wins, because a difference that small is below what the eye can see side by side (CSS Color 4 uses 0.02 as its just-noticeable step in the same space). Whole parts mean you can measure with a spoon or a palette knife: 2 parts Titanium white + 1 part Cadmium red is two scoops of white to one of red.

When even the best mix is rough, the page says which tube is missing. A saturated green cannot be made from a red and a white, so the recipe says none of your paints mixes this; a green tube near the key colour would. Adding a yellow and a blue to the list usually fixes greens; a black or a burnt umber fixes most dark shadows.

Questions

Is this paint by numbers generator free?

Yes. There is no account, no watermark and no limit on how many sheets you make. The PDF, PNG and SVG are yours to print as often as you like. The page runs in your browser, so the only cost is your paper and paint.

How do I turn a photo into a paint by numbers?

Open the photo, choose the sheet size (A4, A3, Letter, square or your canvas in cm or inches), then set the number of colours and the smallest region. The sheet and a painted preview appear side by side; when the preview looks like your photo and the difficulty line suits you, download the PDF. A close crop of one subject with clear light works far better than a wide, busy scene.

Can I make a paint by numbers online without uploading my photo?

Yes. The photo is opened and processed inside this browser tab, in a background worker; it is never sent anywhere. So that your sheet is still there when you come back, the photo and your settings and colour changes are kept in this browser's own storage on this device, until you tap Clear. The page only counts an anonymous visit and seven fixed events (open, download, recipe, easy, smooth, play and play-done).

How many colours should a paint by numbers have?

For a first try at A4, 12 to 18 colours. Fewer colours give fewer, bigger regions and a flatter, poster-like picture; more colours keep skin tones and skies smoother but add regions fast. Watch the difficulty line: it counts the regions and the smallest one in square millimetres, so you can see what a change costs before you print.

How do I mix the colours for a paint by numbers?

Add the paints you own under My paints, by tapping dabs on a photo of a swatch card or typing HEX codes. For every number on the key the page tries every mix of up to 3 of your paints in whole parts, up to 12 parts, with a Kubelka–Munk pigment model, and shows the best one, such as 2 parts white + 1 part red, with the predicted colour beside the key colour and a word for how close it is. The recipes print under each number on the PDF key page and copy as plain text. Mix a small dab first: real pigments shift the prediction.

Can I print a big canvas, like 40 × 50 cm?

Yes. Choose Canvas size and type the size in cm or inches. The PDF keeps the outline at true size and splits it over as many A4, A3 or Letter pages as it needs, each repeating 10 mm of its neighbour with a dashed overlap line, so you can tape the pages together or trace them onto the canvas. A 60 × 80 cm canvas takes 12 A4 pages plus the key.

Can I paint by numbers online instead of printing?

Yes. Make the sheet, then tap Paint on screen under Download. The numbered outline opens full screen with the colour key as a bar of numbers. Pick a number and its blank areas are tinted (the tiny ones get a ring), then tap an area: if it is that number it fills with the colour; if not, nothing fills and the area shows its own number for a moment. Pinch or scroll to zoom and drag to move. A counter says how many areas are painted, a tick marks each finished number, and when every area is filled you can download the painted picture as a PNG. The progress is kept in this browser on this device, so you can close the page and carry on later; it does not follow you to another device.