Convert PDF to Black and White

How to Convert PDF to Black and White

1. 1

   Choose a PDF

   Drop one PDF on the tool, choose it from your files or paste it.

2. 2

   Pick a mode

   Choose grayscale, black and white or inverted, and check the live preview of page 1.

3. 3

   Convert and download

   Press the button and save the new PDF, which has the mode added to its name.

Make PDF Black and White in Three Modes

The tool has three modes. Grayscale keeps every page in smooth shades of gray. Black and white uses only black and white, with nothing in between. Inverted swaps every color for its opposite, so a white page turns black. Pick one mode, watch the live preview of page 1, then convert the whole PDF.

• Grayscale: photos and shading stay smooth, and no color is left in the file. This is the way to convert a PDF to grayscale.
• Black and white: crisp text and the smallest file. Best for text, forms and line drawings.
• Inverted: light text on a dark page, for reading in the dark.

The mode applies to every page of one PDF. Page size, page order and the title and author stored in the PDF stay the same. The result is a new file, so your original is not changed.

Pure Black and White Mode

In black and white mode, each pixel becomes black or white. Nothing in between is kept, so text is crisp and the file is by far the smallest. Photos and light gray shading turn into solid black or white. Use this mode for text, forms and line drawings, and grayscale for pages with pictures.

The tool finds the cut between black and white for each page itself, using a standard method called Otsu's method. A slider, shown only in this mode, moves the cut. The middle is automatic. Right gives bolder text, good for faint print. Left gives thinner text, good for a gray background. It runs from 60 lighter to 60 darker in steps of 5.

PDF Dark Mode: Invert PDF Colors

Inverted mode turns a PDF into a dark mode PDF. Every color is replaced by its opposite, so white paper becomes black and black text becomes white. That means less glare when you read in the dark. Photos are inverted too and look like negatives, so it suits pages of text best.

The result is a new PDF that is dark in every viewer. It is not a viewer setting, and your original stays as it is. To give a PDF the look of a paper scan instead, make the PDF look scanned.

File Size and Limits

Every page of the result is drawn as an image and placed on a page of the original size. Its text cannot be selected, searched or copied, and links, form fields and bookmarks are gone. Keep the original. If you need the words, get the text out of the PDF first. For the same reason, crop the PDF or watermark it before you convert, while it still holds real text.

A PDF made of real text gets larger, because real text is tiny and images are not. A 12-page PDF of 11 KB became about 560 KB in grayscale and about 170 KB in black and white. A 9-page scan of 841 KB became 747 KB in grayscale, 99 KB in black and white and 874 KB inverted.

On letter-size pages, a black and white page takes about 10 to 40 KB, and a grayscale page about 50 to 130 KB. At the limit of 150 pages full of text, that is about 6 MB in black and white against about 19 MB in grayscale.

• Up to 100 MB and 150 pages on a computer. Up to 30 MB and 40 pages on a phone, because a phone browser has less memory.
• Grayscale and inverted pages are drawn at 200 dpi on a computer and 150 dpi on a phone. Black and white pages use 300 dpi and 225 dpi, to keep letter edges smooth.
• Very large pages, such as posters and plans, are drawn at a lower resolution, because one page image is capped at 16 megapixels.
• A password-protected PDF has to be unlocked first. Save a copy without the password.
• One PDF at a time, with the same mode for all its pages. PDF only.

Frequently Asked Questions

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