rich2005 wrote:
You can get carried away with technicalities and overlook the obvious.
The first thing I thought was 'fast-fourier-transform' (maxed out the cpu with this one, lol) or maybe a 'wavelet-denoise'
but a simple filters -> generic -> erode works just as well with this image. The face and the hands do suffer, so work on a duplicated layer then add a layer mask and restore those areas.
wwwooooowww, thank you for your suggestion. The erode filter is top notch

. I didn't even realize that filter exists before you told me LOL.
Below is my result. After I apply erode filter (masking hands and face), I apply bilateral filtering and anisotropic smoothing. Should have done once more for the grain in the background.
Attachment:
galileo galilei.jpg [ 429.53 KiB | Viewed 2362 times ]