How Compress PDF works

Compress PDF makes a smaller copy of a PDF. Start with the high setting so letters that are already real text stay selectable.

Medium and low settings can flatten pages into pictures. That shrinks photo-heavy files and also makes the text blurry.

Steps

1. Drop the PDF and choose a quality.
2. Download the smaller file.
3. Open a paragraph and a logo and zoom in.
4. If the size barely changed, the file may already be lean, or it may be a scan.

Limits

Compression does not invent a text layer. A scanned book stays large because the pixels are large.

Which button keeps real text

Better quality copies the pages and rewrites the file with object streams. Selectable text stays selectable. Use this first.

Balanced redraws each page as a JPEG at scale 2 and quality 0.92. Smallest uses scale 1.45 and quality 0.82. Both replace the page with a picture. Do that only when you can accept blur and you no longer need to copy the words.