Kodak Portra film has both a Green and Red sensitivity of about 2.0 relative log E with a maximum speed of 2.5, so it is pretty sensitive in the region of the visible spectrum of Sodium lamps. That is how it works to give us a yellow in the final print.

I know color reproduction well enough to design films and papers and to be the person responsible for color reproduction of 3 major products AAMOF.

To paraphrase Klaatu in the original movie "I know the math well enough to navigate between planets!" I used this in answer to one of the 24 or so PMs today about this thread. I hope that the quote is not lost on you all and explains my growing exasperation.

PE