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SlimFile.app

Convert a PDF to greyscale

Convert the pictures in a PDF to grey. Up to 10 at a time, 25 MB each.

Choose your PDFs

up to 10 at a time.

PDFMax 25 MB each

How it works

  1. Step 1

    Drop a PDF

    Drag up to 10 PDFs onto the page, or browse for them. Each can be up to 25 MB.

  2. Step 2

    Convert to grey

    Every colour picture in the document is converted in place.

  3. Step 3

    Download it

    Usually a good deal smaller, and cheaper to print.

What gets converted, and what does not

This converts the pictures in a document to grey and leaves the text alone. That is a deliberate limit rather than an oversight: recolouring text means rewriting the colour instructions in every content stream, which is a risky operation on a document someone still has to read. In practice the colour that costs money at a print shop is in the photographs, and body text is usually black already. If you have coloured headings that must print grey too, your printer's own greyscale setting will handle them at print time.

Images
every colour picture is converted to grey
Text
left exactly as it is, and still selectable
Size
grey images hold a third of the data, so the file usually shrinks

Why use SlimFile.app for this

  • Often much smaller

    A grey pixel holds a third of the data of a colour one, so photo-heavy documents shrink considerably.

  • Text is left alone

    Only images are converted, so the text stays exactly as it was and fully selectable.

  • Free, no sign-up

    No account, no email address, no trial that runs out.

  • No watermark

    What you download is clean — nothing added to your file.

  • Deleted within an hour

    Uploads and results are removed automatically about an hour after processing. We never look inside them.

Questions

How do I convert a PDF to black and white for printing?
Add the PDF and every colour image becomes greyscale. Coloured text is kept as it is, so for a fully grey printout also choose your printer's greyscale setting.
Does it convert the text too?
No, and that is deliberate. Recolouring text means rewriting the colour instructions inside every content stream, which is a risky thing to do to a document someone still has to read. In practice the colour that costs money at a print shop is in the photographs, and body text is usually black already.
What if I have coloured headings?
They stay coloured. If they must come out grey as well, your printer own greyscale or black-and-white setting will handle the whole page at print time, which is the safer place to do it.
Will the file get smaller?
Usually, and often by a lot. A grey pixel holds a third of the data of a colour one, so a document full of photographs can shrink considerably. A document with only one small logo will barely change.
Can I undo it?
Not from the converted file — the colour information is gone once the images are rewritten. Keep your original if you might need it.

Read more

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