Hi there,
I just wanted to say that if you still have the original footage, it will be much easier to get a higher quality transfer than touching up each frame. You need to make sure that the company transferring your film scans it properly rather than projecting it on to a screen and filming it with a camcorder.
There are a few companies that will do this for you:
https://www.cinetodvdtransfer.co.uk/
https://www.maxcommunications.co.uk/blog.html
https://www.savethosememories.co.uk/news
Hope this helps.