An interesting side note about salt
In an earlier post you will recall the engineer's admonition to not use ordinary grocery store salt due to the Sodium silicoaluminate anti-caking agent "when it rains, it pours". So the next night I purchased 100% pure salt in the same size plastic tube. The standard salt weighed 26 oz, and the Kosher pure was marked 13oz. Both had roughly the same volume in the tube, And since both were freshly opened there was no time for any hygroscopic tendencies to cloud a remarkable conclusion I made. And that is, that ordinary grocery store salt does not have "trace amounts" of the anti-caking agent. There's a LOT in that tube that is not salt, but sodium-whatever. I would have not had any idea that they would put that much of it in there with the salt. And it must be a heavy chemical because it weights twice as much. And the taste--Kosher salt is hardly salty tasting at all compared to the treated salt.
I hate to think of the mess I would have made of my film if I had ignored the advice and proceeded with the treated salt. Indeed, I may never buy that kind of salt again.