Editing pdf in Illustrator - high res pictures from Ai are low quality when saved back to .pdf, why?

[Z0W3R_NX5]

Hello, please help.

i have a 40 page document in .pdf, that i need to slightly edit - pictures and some graphic elements, mostly text. So the text part is kind of easy, but the pictures are causing me troubles. For example, i edit a page, insert a high res - 300dpi tiff file in the illustrator, save the page, and review it in acrobat, the text and graphics are spot on, but the picture looks like it is 50dpi, super bad quality, unusable for print. (see the attachment below, how the pictures turn out looking)

Is there something i am missing, some settings in acrobat that are converting the pictures to being low quality or some other techniques to use to import high quality pictures to acrobat?

Hope it makes sense. English is not my native language, sorry for grammar errors.

Thanks in advance for help, have a nice day you all.

[Mylenium · Accepted solution]

Start by checking your document DPI settings and of course the PDF Preset details on save. The latter more than anything else bears influence on the PDF quality and operates utterly independent from the host program's settings.

Mylenium

[Z0W3R_NX5]

Sure enough, my illustrator .pdf export settings were set from last time i used it to "smallest file size possible". I honestly did not think of that at all, thanks for reminding, that solved my issue. Have a nice day.

Solution for anyone who might have the same issue is to change the .pdf quality in illustrator when saving the file to high print or anything that suite your needs.

Cheers