# Grayscale & Flatten PDF — Flatten or convert a PDF to grayscale on Mac

Make print-ready copies: lock form fields and annotations into the page, or convert to black and white. Part of OneMacTools, 151 private tools in one native Mac app (macOS 26 or later); category: PDF. Runs on your Mac; nothing is uploaded.

Flattening burns form fields, comments and annotations into the page so they can't be edited. Grayscale converts every page to black and white for cheaper printing and keeps the text searchable.

Page: https://www.onemactools.com/tools/grayscale-flatten-pdf · Download: https://www.onemactools.com/download · Pricing: https://www.onemactools.com/pricing

## How to use it
1. **Add the PDF.** Drop one or more PDFs onto Grayscale & Flatten PDF.
2. **Choose what to make.** Set Make to Flattened, Grayscale, or Grayscale + flattened.
3. **Set the grayscale quality.** For the grayscale modes, pick 150, 200 or 300 dpi and decide whether to keep the text searchable.
4. **Click Convert.** A copy ending in “flattened” or “grayscale” is saved in a dated folder in Downloads › OneMacTools. Open it with the Preview (eye) button to check.

## Options
- **Make:** Flattened (forms locked in) burns form fields, comments and other annotations into the page so they can't be edited. Grayscale turns every page black and white. Grayscale + flattened does both.
- **Grayscale quality:** Only shown for Grayscale and Grayscale + flattened. 150, 200 or 300 dpi (200 by default). Higher keeps small print crisper but makes a bigger file.
- **Keep text searchable:** Only shown for Grayscale and Grayscale + flattened. On by default. Grayscale pages are saved as images, so this reads the text on each page and adds an invisible text layer, letting you search and copy it again.

## Tips
- Flatten a filled-in form before sending it, so the answers can't be changed or lost when someone opens it in another app.
- Flattening on its own keeps text and drawings sharp, as the pages aren't turned into images.
- Grayscale pages become images, so choose 300 dpi for documents with small print, and 150 dpi when a small file matters more.
- Grayscale is a good way to preview how a colour chart or highlighted document will look from a black-and-white printer.
- Form answers, links and comments stay on the page when you sign, watermark or number it. Flatten first only if you want filled-in answers fixed so they can't be edited.

## Questions
**How do I flatten a PDF on a Mac?**
Drop it onto Grayscale & Flatten PDF, set Make to Flattened (forms locked in) and click Convert. Form fields, comments and annotations become part of the page.

**What does flattening a PDF mean?**
Filled-in fields and comments normally sit on top of the page and can be edited. Flattening draws them into the page itself, so they look the same everywhere and can't be changed.

**How do I convert a PDF to black and white?**
Choose Grayscale, pick the quality and click Convert. Every page is turned to shades of grey, ready for cheaper printing.

**Will a grayscale PDF still be searchable?**
Yes, with Keep text searchable on. The text on each page is read on your Mac and added as an invisible layer you can search and copy.

**Why is my grayscale PDF bigger than the original?**
Grayscale pages are saved as images, which can take more space than typed text. Choose 150 dpi for a smaller file, or run Compress PDF afterwards.