Picture Control Utility 2 which can be found in Nikon Capture NX-D or Nikon ViewNX2 software programs (as of June 26, 2014) or Nikon ViewNX-i software (as of March 2015).
I am having trouble with the results between the 2 cameras. I can’t remember if I applied a linear curve for the D3 before.
There is this curve that is allegedly even better than linear for the D7100 but everything is SUPER dark. I need to try some real pictures.