ref: https://fstoppers.com/education/speed-your-retouching-six-easy-tips-75929
ref: * http://www.thephoblographer.com/2011/09/26/are-tiffs-and-raws-really-the-same-thing/
Because
We achieve the same thing digitally with free photo eiditing software, Krita or GIMP.
Of course, before any below method, please use heal brush or patch tool to fix big holes of skins
Overlay + Invert + Highpass Filter (blur) + Gaussian Blur Filter (sharp) Method
Highpass filter (3x,18), Gaussian Blur (1x, 6), Invert, Linear Light mode (corner blend option)
Median Filter (10)
Surface Blur Filter (5,15)
Highpass Filter (10), De-saturate, Invert, Softlight/Hardlight mode
Summary of all above method and theories behind it:
and more scientific accurate way of detail (high frequency image data) and smooth area (low frequency image data)seperation and process