35mm print film or slides for best conversion to digital?

serious photographers will use a diapositive (slide) film and have them printed on paper. You will get the best results from the slide film and not the print film.

You have to be careful, though. If your camera is not adjusted to be completely correct on shutter speed and stops, they the slide film will not be that good. When you use print film, you have a bit of latitude regarding such problems, probably a stop or two either way. You don't have that latitude with slides - what you see is what you get.

I'm gathering that you have a flatbed scanner. I am also gathering that your originals are too large to fit that scanner or you wouldn't ask this question. You'd just do a scan of the original.

You would probably make out better scanning film. Since you can scan slides or negatives, you decide. Personally, I'd get some low ISO slide film and use that. (Kodachrome or Ektachrome 64) It's just more convenient to scan slides in my scanner.

I can scan up to 4800 ppi in the Nikon Coolscan V-ED and make monstrous prints from that scan.

I can scan up to 9600 ppi on my Epson scanner, though. That's twice the resolution and the source would be a 4x6 print, so that sounds pretty good. The problem is, the print resolution is not likely to be nearly as good as the negative or slide is in the first place.

Since the top contributor didn't answer either question, "What film do you recommend?", or "35mm print film or slides for best conversion to digital?" I will.

Slides have less latitude for error than film so seek a good portrait film (white reproduction and skin tone) that will replicate your image more accurately. I like Sensia as my own choice but I don't know if Fuji is still making it anymore (I'm a slide or digital shooter anymore). Kodak Portra 160NC is another great reproductive film.