I wonder what Brian Shaw said before he deleted it. He's one of the reputable names on here. I'd have liked to heard it. I wish the one site I found a data sheet on the CdS cell had not passworded their PDF, so I could bring it into photoshop and crop the response curve to post here. It was very enlightening. But suffice to say it was VERY peaked in it's sensitivity range. Enough to make you wonder how these meters are calibrated and what film speed compensation must be considered outside that peak. And another thing--back before about 1970, B&W film had a daylight rating and a tungsten rating. I always assumed it was the film. Now I wonder if it was because of meter color sensitivity. And if so, why doesn't the film manufacturer have a tungsten rating now? Why did they drop it?