While I prefer to stay with PI 100% I do find there are times when I slip back into PS usage and one of these areas is with final noise reduction. It’s very possible in PI, in fact there are a number of ways to do so, but if I’m pushed for time I’ll open the image (usually in 16 bit TIFF format if I’m in PS now), create a copy and create a mask in the copy and use noise reduction in PS as an initial start. I follow this video as a method to start and then I select the layer the noise reduction is being done in and use Noise Ninja on the image to reduce noise only in the background. The same type of method can be done in PI but I haven’t really figured it out just yet. There are also a number of forum threads on PI that address this very subject. I do it this way sometimes because I already owned the software.

Steve