About the Black and White Image
Tezmy's Black and White Image takes the colour out of your photos in three ways. Grey turns every colour into the matching shade of grey, like a classic black and white photo. High contrast makes pale greys white and dark greys black, which cleans up photos of documents and whiteboards. Pure black and white leaves only black or white pixels, with a slider to choose where the line falls, which suits signatures, stamps, logos and line drawings. Add one photo or many; each is converted at full size, and you can download them one by one or all together as a ZIP. Everything happens in your browser.
Updated October 2026
How to use the Black and White Image
- 1Tap Select images and pick one or more photos.
- 2Choose Grey, High contrast or Pure black & white.
- 3For pure black and white, move the threshold slider until it looks right.
- 4Download each image, or all of them as a ZIP.
Three kinds of black and white
- Grey: the classic black and white photo. Colours are turned into grey by how bright they look to the eye (green looks lighter than blue), so the picture keeps its depth.
- High contrast: grey with the ends pushed further apart. The palest greys become white and the darkest become black, while the middle tones spread out smoothly. Good for documents, drawings and dull photos.
- Pure black and white: every pixel is either black or white. You choose the dividing line with the threshold slider.
Getting a clean signature or stamp
Photograph the signature on plain white paper in good light, crop it close with Crop Image, then choose Pure black & white here. If the background still has grey smudges, move the slider left; if the pen lines break up, move it right. Save as PNG for sharp edges.
Forms that ask for a small file can then be met with Compress Image or Resize Signature to 20KB, since a black and white picture compresses very well.
Tips for better black and white photos
- Photos with strong light and shadow, texture or clear shapes look best without colour.
- If a portrait looks flat in Grey, try High contrast for more punch.
- Pure black and white is not meant for portraits: faces lose their shading. Use it for graphics and text.
- To keep a transparent background (for example a logo), choose PNG. JPG fills transparent areas with white.
Phone or computer
It works in Safari, Chrome and Edge on iPhone, Android, Windows and Mac. Large photos from modern phones (12 to 48 megapixels) take a second or two each. On a phone, the ZIP download lands in Files or Downloads; single images can be saved to your gallery from there. Nothing is uploaded at any point. If you want to send it as a PDF, Grayscale PDF does the same for whole documents, and Image Converter changes the file type.
Features
- Grey, high contrast or pure black and white
- Threshold slider for pure black and white
- Many images at once, ZIP download
- Full size, no quality loss from resizing
- Save as JPG or PNG (keeps transparency)
- Private: photos never leave your device
Frequently asked questions
How do I make a photo black and white?
Select the photo, keep Grey chosen and tap the download button next to it once the preview turns grey. For several photos, select them all at once and use Download all (.zip).
What's the difference between grey and pure black and white?
Grey (grayscale) keeps all the shades between black and white, so photos keep their detail. Pure black and white has only two colours: every pixel becomes black or white. That looks harsh on photos but is perfect for signatures, stamps, logos, QR codes and scanned text.
What does the threshold slider do?
It sets how dark a pixel must be to turn black. At 128 (the middle) anything darker than mid-grey becomes black. Move it right to make more of the picture black (thicker lines, darker text) and left to make more of it white (cleaner background).
When should I use High contrast?
For photos of paper: notes, receipts, forms and whiteboards. It whitens the greyish or yellowish background and darkens the writing while keeping smooth edges, so the text is easier to read and print.
Does it reduce the size or quality of my photo?
No. The image keeps its full width and height. JPG files are saved at high quality; choose PNG if you want no compression at all or need to keep a transparent background.
Are my photos uploaded?
No. The conversion is done by your browser on your own phone or computer, and nothing is sent to a server.
Can I convert many images at once?
Yes. Pick as many as you like; they're converted one after another with the same settings, and changing a setting redoes them all. Download all (.zip) saves everything in one file.