How Can I Compress a PDF Without Losing Quality?

Hi — yes, in Acrobat Pro you can do this directly, and the key is to compress in one pass at the right quality level instead of compressing the same file over and over.

Easiest method in Acrobat Pro:

1. Open the PDF in Acrobat Pro.

2. Go to All tools > Compress a PDF (in older versions: Tools > Compress PDF).

3. Choose the file, then pick a compression level — for email/sharing with photos, choose Medium or High quality rather than the smallest size. Click Compress, then save the result under a new name so you keep the original.

4. Check the result at 100% zoom. If text is still readable and photos look clean, you are done.

For more control (best for image-heavy files):

1. Go to File > Save As Other > Optimized PDF (or File > Reduce File Size for a quick version).

2. In Optimized PDF, go to Images. Set color and grayscale images to downsample to about 150 ppi for on-screen/email use (300 ppi only if it will be printed), and use JPEG quality Medium-High.

3. Under Fonts, make sure fonts are embedded, and under Discard Objects, you can remove things like hidden layers and embedded thumbnails. Click OK and save with a new name.

Two tips that make the biggest difference:

- As gary_sc noted, resize oversized photos before they go into the PDF. A photo straight from a camera at 4000+ pixels wide does not need to be that large in a document that will be viewed on screen.

- Compress once from the original, not from an already-compressed copy. Each extra pass loses more detail.

If you need the smallest possible file for email, use the Low/Medium setting and check the file size in File > Properties. For print, do not go below 300 ppi / High quality.

Hi, ​@Playful_Rocket5079, probably one of the most overlooked mechanisms to reduce a PDF that has images is to make sure the images are no larger than necessary. 

Probably the biggest waste of storage space is having images that are original size out of the camera put into a small space. Let me make up some numbers here for you. Let’s say you have an image who’s original size is 4000 by 3000 pixels (12 megapixels). Every time you reduce the size of an image by ½, your storage size goes down by ¾ quarters. Considering that a 300 dpi image that is 3” wide, that’s 900 pixels wide. You see where I’m going with this. When you take an image that’s 4000 pixels wide and make it fit into an area that’s 3” wide, it’s still a 4000 pixel wide image.

Hi Playful_Rocket5079,

Thank you for reaching out.

Please try reducing the file size using the steps suggested in the following help document: Reduce PDF file size with advanced options. 

Let us know if you have any questions.

Thanks,

Meenakshi