Posting black and white music scores in pdf format Finale from makes the lines very fuzzy.

PDF files are a compatible file format in Keynote, most themes created by Apple for Keynote contain PDF files successfully.

the next time I worked with the PDF files on the slide are now fuzzy.

• Where did you get these PDF files, did you create them?
• What did you do to the slide or the PDF?
• Open the same PDF in Preview app and in Keynote and compare the visual quality, is there a difference?
• using the Finder, go to the PDF file, right click and select Get Info:

what is the resolution in pixels?

what is the file size in KB or MB?

Finale supports exporting to scalable vector graphics (SVG) content and Keynote v13.1 supports dropping the SVG content on it as document objects. If you are creating a PDF from Finale, instead try exporting the content to SVG and see if that vector graphics output is sharper than what you are now seeing in the PDF.