[Wish List - Add Grain]

Grain size seems like a good option as well, and is harder to manually.

Like, I found the manual way to do grain in "photoshop tutorials", but there doesn't seem to be a way to get "grain size" manually.

Like, to make grain manually
1.) new filter > fill > 50% grey (HSL, L is 50)
2.) noise > add noise (Gaussian & monochromatic) 
3.) blend mode: overlay (or soft light, also good)
4.) blur > Gaussian blur (0.2-0.8 px blur = makes noise turn into "grain", the secret ingredient) 

but then to get grain size, that's just scaling a raster image = pixels! (NOT GRAIN!)
so, doing it manually isn't perfect I've found out.