SantoshTec PDF

Convert a PDF to black and white

Turn colour pages into greyscale for printing or for portals that insist on black and white. Convert the whole document or only the pages you choose, at the quality you need.

Drop the PDF to convert to greyscale

Handled entirely on this device.

    Load a PDF to see its page count.
    Lower makes a smaller file. Below 70, edges of text start to blur.

    Files are processed in your browser. Check the available result or preview before downloading; some tools return text, images or metadata instead of PDF pages.

    Using Greyscale PDF, step by step

    1. Drop the colour PDF onto the box above.
    2. Choose every page or only some, and the resolution. 150 DPI suits most documents.
    3. Press Convert to greyscale and look closely at the preview, especially charts and highlighted text.
    4. Download the black and white copy.

    When you need black and white

    Printing. Colour pages cost several times more to print than black and white, and many office printers will use colour ink for a page that is mostly grey if a single logo is in colour. Converting first guarantees the cheaper rate and avoids surprises like a pale red heading that prints almost invisibly.

    Upload portals. Some government, visa and examination portals ask for scanned documents "in black and white" or "in greyscale", partly to keep file sizes down. A colour phone scan of a certificate is often rejected for exactly this reason.

    Smaller files. A colour photo of a page carries three channels of information; a greyscale one carries one. For scans and photographs, converting usually shrinks the file.

    Greyscale is not the same as pure black and white

    Greyscale keeps every shade from white to black, so photographs, signatures and stamps still look natural and pale pencil marks remain visible. Pure black and white — one bit per pixel, as a fax machine produces — throws away every shade and turns light marks into nothing. When a form asks for "black and white", greyscale is almost always what they mean, and it is what this tool produces.

    How it works, and what it costs

    Each page you choose is drawn at the resolution you pick, converted to greyscale using the same weighting the eye uses for brightness, and saved as an image. Pages you leave out are copied across unchanged. Because converted pages become pictures, their text can no longer be selected or searched. For a scan that makes no difference, since it was a picture already. For a typed document it means the file may grow rather than shrink; if that happens, try 120 or 150 DPI.

    Check colour-coded content

    Colour sometimes carries meaning: a red line and a green line on a chart, or highlighted rows in a table. In greyscale, red and green of similar brightness become the same grey. Before you send the converted file, look at any chart, map or highlighted text in the preview and make sure it still makes sense. If it does not, convert only the pages that need it using Only some pages.

    If the real problem is file size rather than colour, Compress PDF may be a better first step.

    Frequently asked questions

    Will the text still be selectable?

    Not on converted pages, because they become images. Pages you do not select keep their original text. If you need searchable text, convert only the pages that must be black and white.

    Why is my greyscale file bigger than the original?

    The original was mostly text, which is very compact. As images, those pages take more space. Choose a lower resolution, such as 120 or 150 DPI, or lower the quality slider.

    Is this the same as the greyscale option in Compress PDF?

    They work in the same way. This tool gives you control over which pages are converted and at what resolution, and its aim is a faithful black and white copy rather than the smallest possible file.

    Does it work on scanned documents?

    Yes, and scans are where it works best: they are already images, so the conversion usually makes the file smaller too.

    Is my PDF uploaded?

    No. The conversion happens in your browser on your own device.

    Guides that use this tool

    Background and practical advice from the guides section.

    Related PDF tools

    Most jobs need two or three steps. These pair well with Greyscale PDF.