"Reduce File Size..." Resolution concerns

While I am not sure of this, I suspect that the "Reduce File Size..." option is, in some way, using PDF Optimizer as the feature's dialog describes saving to an earlier PDF version.

If you process your PDF files with PDF Optimizer you will have a plethora of configuration settings available for images and other aspects of the PDF file(s). The Acrobat Help provides discussion on using PDF Optimizer.

The Standard, out-of-the-box, setting uses downsampling and JPEG compression for any images in the PDF.
If "Reduce File Size..." pulls from this then image degradation would be expected.

The degradation may or may not be readily noticable. Regardless, downsample removes pixels and JPEG compression is a lossy vice lossless compression mechanism.
These can adversely impact the effective resolution of your image which can adversely impact what you "see".

Be well...

Thanks, I think you are correct. I also did some tests turning "Reduce File Size" on and off. There is some resolution loss although it affects some images more than others. To be on the safe side I will not use it until I figure out the PDF Optimizer! Thank you again.

daka630 is correct.

In general, you remove information (by down-sampling and compressing images) when you reduce file size. Press-Ready PDF files are often quite large, and reducing the file's size is not recommended (by most printers I know of). Reduce File Size is the younger sibling of the PDF Optimizer, and just takes a good hearty swing at reducing the file's size. You should never use this for press-ready PDF files (or images in a print project in general).

Discuss PDF setting with your print vendor, create PDF files to those settings, and then bear with the file's size.

Thanks for weighing in! I've learned my lesson!

Create a custom pdf optimizer settings. I made one and it's been great for reducing the file size and there is not noticeable loss resolution. Do this:
1. Open a file in acrobat
2. File> pdf optimizer
3. Under "images" Choose: average downsampling 300 ppi, compression jpeg "maximum" Do this for grayscale and color images. Under monochrome images pick the same but choose CCITT group 4 for the compression
4.Under "transparency" choose "high resolution"
5. Under "discard objects" check all the boxes
6.Under "discard user data" check all the boxes
7.Under "clean up" choose "make compatible with acrobat 5 and later, "compress document structure" and check all the boxes again.
8. Click the "save" button on the top of the window
9. Give these settings a name (mine is called jpeg300)

Next time you have a HUGE pdf file, optimize it using your saved settings and it will significantly reduce the file size. I've done a lot of print marketing materials this way and my printer has no problem with my files and I have not noticed any significant loss of resolution.

I do have "print ready" documents I need to send out to customers, but they are so big they are hard to handle by my (or their) outlook or email program. Zipping doesn't seem to be an option, and I've tried using my cloud database platform (salesforce.com) to send them, with spotty results. Any suggestions to make my pretty 1meg+ documents more manageable?
Thanks!