Topaz recently updated DeNoise AI to version 3.1.1 and as is the custom, they are offering free upgrades for current users, $20 off new purchases and an additional 15% off using coupon plugsnpixels here.
A $50 discount and extra 15% off also applies to the entire Topaz Image Quality Bundle (DeNoise AI, Sharpen AI and Gigapixel AI) for an even better deal.
The screenshot below shows some work I did in DeNoise AI just before this latest update (using v3.0.3), effectively removing the nasty noise from a late-1800s image that I copied in person on 35mm film in the 1980s and more recently colorized online:
The new version 3.1.1 now includes 4 modules for different types of treatment:
DeNoise AI is not only very useful for removing analog grain as well as digital noise from your challenged images, it also sharpens and clarifies them as well.