Convert an image to pure black and white
Reduce a picture to two tones with nothing in between. Use a clean cut-off for scans, signatures and line drawings, or dots for a photograph you want to keep readable.
- Runs in your browser
- Nothing is uploaded
- No sign-up
- Batch up to 20 images
Drag & drop your image here
or tap to browse · you can also paste from the clipboard
JPG · PNG · WebP · GIF · BMP · AVIF · SVG · up to 50 MB each · up to 20 files
Choose imagesBefore
After
Processed image will appear here.
How to use the black and white converter
Add the picture and it becomes pure black and white, with the dividing level chosen for that image. For text and signatures keep Automatic or set the level yourself. For photographs choose Dot scatter or Dot pattern, which stand in for the greys.
- Add your imageIt is converted with a cut-off chosen for that picture.
- Pick a styleAutomatic, a level you set, a dot scatter or a dot pattern.
- DownloadPNG by default, which stores two flat tones in very few bytes.
About this tool
There are two ways to get from a full picture to only black and white. The first draws a line through the brightness scale: everything lighter than the line turns white and everything darker turns black. That is ideal for a page of writing, a signature or a logo, where you want paper to be white and ink to be black. This page can pick that line for you, or you can set it.
The second way keeps the greys by faking them. A patch of mid-grey becomes a mix of black and white dots that looks grey from a distance, the trick printed newspapers have always used. Choose a loose scatter for a natural look or a regular pattern for a printed one.
What you get
- Automatic cut-off chosen for each picture
- Manual level for full control
- Two dot styles that keep the look of grey
- Invert to swap black and white
- Batch up to 20 images with one setting
When to use the black and white converter
Scanned documents and notes
A cut-off turns grey paper white and faint ink black, which makes a scan easier to read and much smaller to store.
Signatures for forms
A signature photographed on paper becomes clean black strokes on white, the form most upload portals expect.
Logos and line drawings
Artwork that should have been two tones all along loses the grey fuzz that scanning or screenshots added.
A printed, stamped or photocopied look
The dot styles give a photograph the texture of a newspaper picture or an old computer screen.
Which style for which picture
| Style | How greys are handled | Best for | Avoid for |
|---|---|---|---|
| Automatic | Split at a level chosen per picture | Text, signatures, line art | Photographs |
| Set the level | Split at the level you choose | Scans where Automatic loses faint strokes | Photographs |
| Dot scatter | Irregular dots, denser where darker | Photographs, a natural look | Small text |
| Dot pattern | A regular grid of dots | A printed or retro look | Fine detail |
How it works
Automatic uses Otsu's method. It builds a count of how many pixels there are at each of the 256 brightness levels, then tests every possible dividing point and keeps the one that makes the two resulting groups as different from each other, and as uniform within themselves, as possible. On a scan that point falls in the gap between paper and ink. On a photograph there is no such gap, which is why the result there is arbitrary blotches.
The dot styles are two kinds of dithering. Dot scatter is Floyd-Steinberg error diffusion: each pixel is rounded to black or white, and the amount by which that was wrong is passed on to the neighbours not yet visited, so that over any small patch the proportion of white matches the original brightness. Dot pattern compares each pixel against a repeating 8 × 8 table of levels instead, which gives 64 apparent shades and a regular texture. Because single-pixel dots vanish when a large photo is viewed whole, the dots are scaled: the picture is reduced, dithered and then enlarged again without smoothing, so each dot is a clean square.
Common problems and how to fix them
- Thin lines or faint writing disappeared
- They were lighter than the cut-off. Choose "Set the level" and raise it step by step until they return.
- The paper is covered in black specks
- The cut-off is too high, so the texture of the paper counts as ink. Choose "Set the level" and lower it. Uneven lighting across a photographed page has the same effect on its darker side; retake the photo in even light if you can.
- I get white on black, and I want the opposite
- Switch on Invert.
- The dots are too fine or too coarse
- Change Dot size. Larger dots survive being viewed small or printed; smaller dots keep more of the picture's detail.
Frequently asked questions
How do I clean up a scanned signature or document?
Use Automatic first. It finds the level that best separates ink from paper in that scan. If faint strokes go missing, switch to "Set the level" and raise it a little so more of the picture counts as black; if the paper comes out speckled, lower it.
Why did my photo turn into blotches?
A plain cut-off has no way to show grey, so a face or a sky becomes solid patches. That is right for text and wrong for photographs. Choose "Dot scatter" or "Dot pattern", which turn greys into dots and keep the picture recognisable.
Is the download a 1-bit file?
No. Every pixel in it is either pure black or pure white, but browsers save PNG and JPG with three colour channels, so a program inspecting the file will call it RGB. It is still small, because two flat tones compress extremely well as PNG.
Why is PNG the default here?
JPG is built for smooth photographs and adds grey smudges around hard black and white edges, which defeats the purpose of having two tones. PNG stores them exactly, and for solid black and white it is usually the smaller file as well.
What is the difference between this and grayscale?
Grayscale keeps all 256 shades from black to white. This page keeps two. If you want an ordinary colourless photograph, use the Grayscale Image converter instead.
Can I make the background transparent instead of white?
Not on this page. White areas are saved as white. To make a solid white background transparent afterwards, use the Background Colour Changer and choose to make a colour transparent.
How small will the file be?
A page of text cut to solid black and white is usually a small fraction of the size of the colour scan, because long runs of identical pixels compress very well as PNG. A dotted photograph is larger, because a field of dots has little repetition for PNG to exploit.