Before we can give you good eadvice we need to know what size the PDF is now, the settings you used to make it, and its intended purpose.
There are a lot of things between these 2 file types that could affect file size, not just a simple choice between one or the other. When you say .ai, do you mean vector artwork or have you embedded graphics into the .ai file?
My own personal preference is to use vector artwork as much as possible (.ai) as I find in most cases this makes the file size smaller. But there are exceptions. If the vector artwork is complicated - lots of layers, lots of nodes, big dimensions, then it might make more sense to export this first as a useable TIFF, PSD or JPEG (bitmap). It will also depend on what your final output is for - web, print etc. If for web, the more bitmap images you use, typically the more you need to downsample the images and they become pixellated. This is also an issue for print but the file size is not such a huge deal in this case.
The pdf size is now 118 MB. I need it to print and to show it on a computer [or on issuu].So, it needs a nice quality.
I'm exporting it using the "export" option and [High Quality Print].
Even when I choose [Smalleste File Size] it has 58 MB.
Thank you for your help.
The Illustrator file is just vector artwork but it has a lot of information. Probably that's the problem.
Because when I see the illustrator link size it has only 1.8 MB.
Vector artwork does not compress, so complex vectors can lead to large file sizes. Live transparency is also a factor.
You said print. Is that print commercailly, or on a desktop printer?
Do you have Acrobat Pro? If so you can go tot he PDF Optimizer and and do a Usage Audit to determine waht is taking up most of the space.
Print Commercially. This is my architecture portfolio. So, as you can imagine, it has a lots of images, plans, etc. And it was pretty clear when I did the Usage Audit - 92.02% - images.
Well, I guess that it is quite normal and we have to choose between quality and size. I tried to export the .ai file to jpeg and tiff.
I wasn't expecting this but then, the exported pdf file from InDesign is smaller with tiff files than with jpeg and illustrator files.
[I hope you can understand my English.]
For commercial printing, and especially for your portfolio, you don't want to try to reduce the size. If you need an online version as well, make a second copy withe the tiffs, but do this understanding that you have traded away a lot of quality for the small size.
Thank you. It was really helpful.