How to minimize pdf file size on mac without losing quality?

Every Mac ships with the Preview app preinstalled, and you can utilize custom Quartz filters instead of the default low-quality preset to reduce the size of PDF files on your Mac without losing quality.

Instructions: Open the PDF file in Preview.

• Select File → Export.
• Open the Quartz Filters drop-down menu and select Reduce File Size.
• Check the exported document; if the image quality has noticeably deteriorated, create a custom compression filter.
• To create a custom Quartz filter with lower compression intensity: Launch the ColorSync Utility from Applications → Utilities.
• Select the Filters tab.
• Click the plus sign in the lower-left corner to create a new filter, and name it “My Compression.”
• Configure the parameters: Set “Color Image Quality” to 0.8, “Grayscale Image Quality” to 0.8, “Monochrome Image Quality” to 0.8, and set the “Image Compression Format” to JPEG.
• Save the custom filter.
• Return to the Preview app, go to File → Export, and select your newly created custom filter before saving.

Advantages include: using macOS’s native, built-in software without the need for additional downloads; fully offline, local processing; and balanced compression that preserves image clarity.

Disadvantages include: the process of setting up a custom filter requires multiple steps, and it is only available on Mac devices running macOS.

Notes

• Be sure to save a copy of the original PDF as a backup before compressing it.
• If your PDF contains photos or graphics, do not set the image quality too low.
• If you need to compress multiple PDFs at once, you can combine this method with Automator to automate the process.

This workflow helps you compress PDF documents efficiently. It’s ideal for users who want to minimize pdf file size mac without losing quality and who want to avoid the overly compressed, low-resolution PDFs generated by the Preview app’s default filters.