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PDF to Grayscale — Desaturate Color PDFs Online

Desaturate color PDFs to grayscale in your browser. Your files never leave your device — private, secure, no uploads.

● LOCAL · DOCS NEVER LEAVE DEVICE0 network requests from tools since page load

Drop your PDF here

or click to browse (max 100 MB)

Grayscale is the sensible middle ground between full color and harsh black & white. It preserves luminance detail — the edge of a curve, the gradient on a chart, the halftone in a photo — while stripping away the color that adds bulk and distraction. This tool re-encodes every embedded image in a PDF through a luminance-based desaturation pass, producing single-channel JPEGs that look correct on black & white printers, e-ink screens, and accessibility-focused document viewers.

The process is the same engine that powers the black & white tool: pages are read with pdf.js, images are extracted, drawn to canvas, processed, and re-embedded in a fresh PDF with pdf-lib. The difference is the image filter — instead of thresholding to 1-bit, the grayscale tool applies a proper luminance-weighted channel collapse, which keeps the image perceptually faithful to the original.

If you need some pages to keep their color and others to go grayscale, open the Color Page Filter tool — it lets you pick which pages to desaturate while the rest stay full-color.

How to use

Drop a PDF
Drag a .pdf file into the drop zone, or click to browse. Up to 100 MB; the file is read locally and never leaves your device.
Automatic conversion
Once you drop the file, every embedded image is desaturated to 8-bit grayscale. Progress updates tell you which page is being processed and how many images have been re-encoded.
Download the result
The converted grayscale PDF is ready to download as soon as processing finishes. The page count, re-encoded image count, and size change are displayed before you hit Download.

Frequently asked

What is the difference between grayscale and black & white?

Grayscale preserves 256 shades from white to black through smooth luminance transitions. The black & white tool thresholds every pixel at 50% luminance, producing a 1-bit image — much harsher, with no gray tones at all.

Will text be searchable after conversion?

Yes. The text layer from the original PDF is extracted and re-written as selectable text. Embedded fonts are replaced with a standard serif font, so alignment may shift by a few pixels.

What about scanned PDFs?

For scanned PDFs without a text layer, the scanned images are desaturated but no selectable text is added. The output will still be a grayscale scan. For searchable grayscale output, run OCR before conversion.

Will the output be smaller?

Usually yes. JPEG images in the original PDF may be full-color; after desaturation they are re-encoded as single-channel JPEGs, which tend to be smaller. The saving depends on how many large color images were in the source.

What about form fields and annotations?

They are dropped during rebuild. Form fields, JavaScript actions, embedded fonts, layers, annotations, and digital signatures are all removed. The output is a flat grayscale document.

Limitations

Font substitutionEmbedded fonts are replaced with Times Roman during rebuild. This preserves text content but may cause minor layout shifts, especially in documents that use condensed or decorative fonts.
Vector content is rasterisedCharts, CAD drawings, and vector graphics are flattened to images during the rebuild. The output is no longer resolution-independent.
No form fields or annotationsForm fields, JavaScript actions, embedded fonts, layers, and digital signatures are dropped. The output is a flat document.
Not a substitute for OCRScanned PDFs without a text layer will produce a grayscale scan with no searchable text. Run OCR first if you need selectable text.

Platform notes

macOS: Works in Safari 16+, Chrome, and Firefox. macOS Preview has a built-in Quartz grayscale filter, but it cannot handle batch conversion or preview the result page by page.
Windows: Edge and Chrome work well. Adobe Acrobat Pro can convert to grayscale via Print Production > Convert Colors, but this tool is faster for a single document and doesn't require a license.
Linux: Runs in any modern browser. Ghostscript with -sColorConversionStrategy=Gray gives the same result from the command line, but this tool lets you convert without installing Ghostscript.
iOS: Safari on iOS 16+ supports the canvas pipeline. On older iOS, very large images (~4000px on the long side) may fail the canvas encoding and fall back to the original image data.