Why do some PDFs become larger after compressing in Adobe Acrobat?

[Flamboyant_dynamism0533]

Hey,

I tried using “Reduce File Size” in Acrobat, but for some reason, a few of my PDFs actually ended up bigger instead of smaller.

Am I missing a setting, or is this normal depending on the file type (like scanned vs digital PDFs)?

Would love to understand why that happens.

[try67]

Very hard to say without seeing an actual file, before and after you ran the command on it.