Selections and masks are subtly different, and the ‘parametric’ masks in non-destructive editors give more flexibility than ever.
Luminance masks
A Linear DNG is a special type of raw file where the raw data has been 'demosaiced', which is the first stage of raw processing, and otherwise modified, but can still be edited and manipulated like a regular raw file afterwards. It's a way to apply specialized lens corrections or denoising, for example, without losing that raw 'edibility'.
Local adjustments explained
‘Local adjustments’ is a bit of a catch-all term. It means picking out an area of an image for adjustment while leaving the rest unchanged. So how do local adjustments work and which software does them best?