You can dye factory-manufactured film to modify spectral sensitivity. Some dyes require lower adsorption density to be effective than others, and these are the ones you want to use if you want to apply a dye on pre-manufactured materials. Many infrared dyes can be used in this fashion but there aren't many dyes for visible light that can be used effectively for this application. If what you want is panchromatic, it's easiest and probably cheapest to buy the finished film. Good cyanin dyes aren't cheap.

But there are people who soak pan film in infrared dye bath to make infrared films. Big PITA but that is an option for nice fine grain IR film after discontinuation of Sakura (Konica) IR 750.