Thankfully, as for mobile apps, there are some authentic looking ones out there handling both dust and grain as well as filters based on film stock scans such a

Thankfully, as for mobile apps, there are some authentic looking ones out there handling both dust and grain as well as filters based on film stock scans such as RNI Films. :) No affiliation; it’s just among the best value out there that I’ve found. For computers and Lightroom/Photoshop you have stuff like Replichrone to help.