They have 2 new lines coming out this year. The first is Color Stable IR...it will essentially be CS with a jump in IR numbers. They still plan on carrying both CS and CS-IR since so many people love the original CS. Then they will have a separate high IR film which will bridge the gap between CS and CR. I was told sometime in the first quarter of 2017 for both films.
The formula doesn't account for how a film's color (spectrum) impacts results.
Back when NC passed their net 35 law I was a film sales rep for the state and it was noted how Centaur (PT) auto film would squeak by light meter devices while ATR failed even if they both had the same VLT going on the same VLT glass. Centaur was a more bluish looking smoked film.
Dealer in Burlington metered film from the box and marked the metered VLT on it label. He would have a minimum of five separate boxes of film of the same film product all with various VLTs. He would determine which to use by metering the glass, picking a sample thought to pass and place a small sample to the glass to gain a net reading. If it was off, he would look to another roll with either higher or lower VLT needed to pass.
All variables are not covered though, because you don't know battery charge strength of your meter compared to the one at the inspection station. And even then it has to be the same type meter with the same calibration variance confirmed.
