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Edit & Text

Convert a PDF to black and white

Make a color PDF grayscale — every color turned to its shade of gray, text still selectable — or pure black and white, two tones only, for a form that must be submitted in black and white or a printer with no color. It is done in your browser; nothing is uploaded.

Settings appear once you add a PDF.

Result

Pure black and white is made from pictures of the pages, so its text can no longer be selected.

160

Raise it if faint text disappears, lower it if gray areas come out as black blotches.

Advanced 3
How

Flatten only if a viewer or printer still shows color: every page becomes a picture.

Image sharpness

Done on your device No upload, no queue, no sign-up.

Bytes sent anywhere: 0 B

How to convert a PDF to black and white

Your PDF goes into this browser tab, is drained of color on your device, and comes back as a black-and-white PDF. 0 bytes uploaded

  1. Add your PDFs

    Drop the color PDF. The preview shows page 1 converted before you commit.

  2. Check the settings

    Choose grayscale, which keeps every shade and the selectable text, or pure black and white, two tones only, with a cut-off you can adjust.

  3. Save the result

    Save the result. It looks the same in every viewer and prints in grays, with no color anywhere on the page.

Why it doesn’t upload

Black-and-white copies are usually asked for by an office — a visa application, a court filing, an exam board. The documents are yours and personal; converting them takes nothing more than your own browser, so they are not uploaded anywhere.

Check it in your browser’s Network tab

Worth knowing

  • Grayscale keeps the page as it is and drains the color from how it is displayed. The color is still inside the file, so a program that strips display effects could show it again; flatten to images when that matters.
  • The selectable grayscale relies on a standard PDF blend effect that every current viewer shows. A few old viewers and some printers ignore it — use Flatten to images under Advanced for those.
  • Pure black and white is made from 200 DPI pictures of the pages by default, so text can no longer be selected or searched, and the file can be larger than a text PDF.
  • Form fields, comments and highlights sit on top of the page and keep their colors.

Under the hood

What happens to your file

Grayscale draws a gray rectangle over each page with the Saturation blend mode (ISO 32000 §11.3.5), which keeps every point’s brightness and removes its color, leaving the text selectable. Pure black and white renders each page with pdf.js, converts it to luminance, cuts it at the threshold you set and stores it as a two-tone PNG image.

Runs on pdf-libpdf.js

Reference: ISO 32000-2 (PDF 2.0)

Questions

How do I convert a color PDF to black and white?

Drop the PDF here, leave Grayscale selected and press Convert to black and white. Every color becomes its shade of gray and the text stays selectable. For only two tones — black ink on white paper — choose Pure black and white.

What’s the difference between grayscale and black and white?

Grayscale keeps every shade from white to black, so photos and charts still read. Pure black and white has only two tones: each dot is either black or white, which is what fax machines, some scanners and strict upload forms expect.

Why did faint text or light lines disappear?

In pure black and white, anything lighter than the cut-off turns white. Raise Darkness cut-off so lighter marks count as black, or use Grayscale to keep them as gray.

Will it print without color?

Yes — it prints in grays everywhere, without anyone remembering the “black and white” switch in the print dialog. Whether the printer then uses only its black cartridge for the grays is up to its driver: many do, some mix gray from colors unless told otherwise.

Can I convert only some pages?

Yes. Under Advanced, type the pages, like 1-4. The other pages are copied across unchanged.

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