I have to agree that experimental error can be a factor in some of the curves presented here.
I have what might be a good example of the mismatching of emulsions. Sometime in the 90s, I did a series of tests with TMY because of reports that it lost a lot of contrast when shot using a red filter. I discovered is that there are at least two emulsions that make up the film. One that is fast but low in contrast and one that is slower and higher in contrast. The dominant characteristic is the one that produces the highest density. Problem with TMY is that the slow higher contrast emulsion had a lower sensitivity to the red spectrum than the faster lower contrast emulsion. When shot with a red filter, the higher contrast emulsion moved toward the right exposing more of the lower contrast emulsion. What you got was a very long toe which reached up into the mid-tone areas, and then when the higher contrast emulsion became dominant, an expanded upper tonal range.
I have what might be a good example of the mismatching of emulsions. Sometime in the 90s, I did a series of tests with TMY because of reports that it lost a lot of contrast when shot using a red filter. I discovered is that there are at least two emulsions that make up the film. One that is fast but low in contrast and one that is slower and higher in contrast. The dominant characteristic is the one that produces the highest density. Problem with TMY is that the slow higher contrast emulsion had a lower sensitivity to the red spectrum than the faster lower contrast emulsion. When shot with a red filter, the higher contrast emulsion moved toward the right exposing more of the lower contrast emulsion. What you got was a very long toe which reached up into the mid-tone areas, and then when the higher contrast emulsion became dominant, an expanded upper tonal range.
