Problem automating action

I'm using Photoshop CC 2018. I have been hired to lay out a new version of an old book. All we have of the old book is a PDF that someone scanned some time ago. If I try to place the book via script in an InDesign layout the pages look very distorted. So I experimented by converting a page from the PDF to .tif in Photoshop and placing that in the InDesign layout. The result looked much better. So I extracted each page of the PDF to a separate file and put them in a folder. Each page has a unique filename, such as "Family History 1.pdf." Here's the problem: I set up an action in PS to open one of these pages and save as a .tif. When I try to automate the action, PS opens and saves each PDF to the destination folder, but overwrites each with the same filename. So instead of having 83 .tifs in the destination folder, as I had 83 pdfs in the source folder, I have one .tif, bearing the filename of the first document. I can't figure out what I am doing wrong.