String art generator

How to make string art from a photo

1. Open the photo and crop it: circle or square, zoom and move until the face or object fills the board. Raise the contrast until the dark parts are clearly dark; thread can only add darkness.
2. Set the board: the number of nails, the diameter of the nail ring (or the side of the square) in cm or inches, your thread's thickness and the number of lines. Tap Make string art and watch the lines appear; cancel and change a setting if it is going the wrong way.
3. Print the nail template at 100 %, check the 10 cm line with a ruler, tape the tiles together on the dashed overlap lines and fix the ring to your board.
4. Hammer a nail at every dot (the numbers stay outside the ring), then tear the paper away or leave it under the thread.
5. Tie the thread to the first nail of step 1 and follow the steps in the step player or on the printed list: each step takes the thread straight across to the next nail and once round it.

What it cannot do

• One thread colour per pattern. It does not split a photo into several colours; Invert makes a pattern for light thread on a dark board.
• The preview is a guide. The real result depends on the thread, the nails, the tension and how the thread sits on each nail, so it will look a little different.
• Over 4,000 lines is not offered, and the top settings are slow on a phone. 360 nails and 4,000 lines took about 3 seconds on a desktop computer for our test portrait; a phone takes several times longer, and an older one much longer. Cancel stops it at any point.
• It does not keep your photo. After a reload the saved pattern, the template and the step player still work, but to change the picture you open the photo again.
• Busy scenes come out as grey mush. A face or an object against a plain background works; a group photo or a landscape does not.

What the numbers mean

Nails are numbered from 0, clockwise. On a circle nail 0 is at the top (12 o'clock); on a square it is the top-left corner and the nails run evenly round all four sides. The board size is the diameter of the ring of nails (or the side of the square of nails), not of the wooden board, so leave a margin round it. On a 40 cm ring 200 nails are π × 400 ÷ 200 = 6.3 mm apart, centre to centre.

Each line darkens the model of the picture by your thread's thickness divided by the size of one model pixel: the photo is worked on at 400 × 400 pixels, so on a 40 cm board one pixel is 1 mm and a 0.15 mm thread darkens each pixel it crosses by 15 %. To measure your thread, wind 20 turns tightly side by side round a pencil and divide the width they cover by 20. That is why a thicker thread or a smaller board needs fewer lines, and why the preview, which draws every line at its true width, can be trusted for overall darkness. The first line is the best one anywhere on the board; each later line starts on the nail where the last one ended, so the steps are one continuous thread. It stops early, and says so, if no line would add any darkness.

The thread length is the sum of the straight lines at your board size, plus 10 % for going round each nail and for tension, plus 1 m for the knots at the start and the end.

Questions

Is this string art generator free, or is there an app to download?

It is free and it is this web page: nothing to install, no account, no watermark and no limit. It works in the browser on a phone, a tablet or a computer, and the photo is processed on that device, never uploaded.

Does it give me the string art steps?

Yes, every one. The steps come as a numbered list (1. 0 → 87, 2. 87 → 143 and so on) that you can copy as text or print as a PDF in blocks of 50, and as a step player that shows the current step in large type with Next and Back, the space bar, an optional spoken nail number and a keep-the-screen-on switch. The player remembers the step you are on in this browser, so you can stop tonight and carry on tomorrow.

Can I print a string art pattern with numbers as a PDF?

Yes. The nail template PDF draws the ring of nails at the true size of your board with every nail numbered from 0 clockwise and every tenth nail in bold with a longer tick. A board bigger than the paper is tiled over A4 or Letter pages with dashed overlap lines, and every page has a 10 cm line to measure so you know the printer did not scale it. A 40 cm ring takes 6 A4 pages.

Can it make colour string art?

No. Each pattern is one thread colour on one board colour. You can choose both colours for the preview, and the Invert switch makes a pattern for light thread on a dark board, but it does not split a photo into several thread colours.

How many nails and lines should I use?

200 nails and 2,500 lines on a 30 to 50 cm board is a good first portrait. More nails give finer detail but put the nails closer together: 200 nails on a 40 cm circle are 6.3 mm apart, 300 are 4.2 mm apart. Fewer lines give a lighter, sketchier picture and less work. Thread thickness matters as much: the thicker the thread for the board, the sooner the picture fills, and the path stops by itself when no line would add darkness (with 0.2 mm thread on a 40 cm ring our test portrait filled at about 2,300 lines).

How much thread do I need for string art?

The page adds up the length of every line at your board size and shows it in metres and feet, plus an allowance of 10 % for wrapping round the nails and tension and 1 m for the knots. On our test portrait, 2,500 lines on 200 nails and a 40 cm ring came to about 885 m including the allowance, so buy a large cone of thread, not a small reel.