PDF to Grayscale
Convert a color PDF to grayscale or true high-contrast black & white — pick a page range and threshold for cheaper, cleaner printing.
How it works: each page in your chosen range is re-rendered, desaturated (or thresholded in Black & White mode), and rebuilt into a new PDF. Pages outside the range are copied over untouched. Note: converted pages are no longer selectable, since they're flattened to images.
How to Convert a PDF to Grayscale
- Upload your PDF.
- Choose a Mode: Grayscale for a full range of gray tones, or Black & White (High Contrast) for a stark, threshold-based look — the Threshold slider appears once you pick it.
- Choose an Output Quality level, and optionally enter a Pages range (e.g. "1-3, 5") to convert only part of the document — leave it blank to convert every page.
- Click "Convert to Grayscale", check the Original Size / New Size stats, then download the result.
Frequently Asked Questions
Will my PDF's text still be selectable after converting to grayscale?
No for pages you choose to convert — like the PDF Compressor, this tool re-renders those pages as an image, desaturates (or thresholds) the pixels, and re-encodes as a JPEG before rebuilding the PDF, so their selectable text becomes part of a flattened image. Pages outside your chosen page range, if you set one, are copied over completely untouched, keeping their original selectable text intact.
How is the grayscale conversion calculated?
Each pixel's red, green, and blue values are combined using the standard luminance-weighted formula (roughly 30% red, 59% green, 11% blue) rather than a simple average, which better matches how the human eye perceives brightness.
Why does the file size change even though I just removed color?
The size change comes from the same re-rendering and JPEG re-encoding process used for compression, not from the grayscale conversion itself — that's also why there's a quality-level selector, since it controls the same scale/quality tradeoff as the PDF Compressor.
What's the difference between Grayscale mode and Black & White (High Contrast) mode?
Grayscale mode keeps a full range of gray tones using the luminance formula above, like a black-and-white photo. Black & White (High Contrast) mode goes further: after computing that same luminance value, each pixel is compared against your Threshold slider (0-255) and snapped to pure black or pure white with no gray in between, similar to a scanned fax or high-contrast photocopy.
Can I convert only some pages instead of the whole document?
Yes — enter a page range like "1-3, 5" in the Pages field. Pages inside that range are rendered and desaturated (or thresholded); every other page is copied over from your original file completely untouched, keeping its original text and quality. Leave the field blank to convert every page, as before.
Does this help with printing costs?
It can — many printers charge more, or use more toner/ink, for pages containing any color, so converting a PDF to grayscale before printing can be cheaper even if the file itself doesn't get much smaller.